Don't worry, Steven, it doesn't matter to me what age it seems like you are, I wanna hang out with you no matter what. Your dad still has to run his car wash, and the Gems have to do Gem stuff, so I'll watch you when they're not around. I can come see you after I'm done training with Pearl too. Doesn't that sound fun?
The Gems are setting up a party for Steven outside of the barn, inflating balloons and fitting them with ribbons. Steven is concerned if it is all right if they stop working on the drill for this occasion, and Pearl assures him that Peridot should keep things in check. Amethyst teases a passing Peridot about the party, failing to amuse her. Garnet reasons that they should celebrate Steven's progress and remarks that he has grown and learned a lot the past year. Connie arrives in Greg's van to celebrate Steven's birthday. Connie explains that it was hard to convince her parents to let her stay in Steven's barn for the weekend and that they refused to let her go without an array of safety equipment, including a defibrillator.
Greg runs up to hug Steven and celebrate Steven's birthday. He is astonished that Steven grew up so fast, seemingly from a baby just yesterday to being fourteen now. Connie is surprised to learn Steven's age and that he is older than her since she is only twelve and three quarters. Greg shows Connie a photo album of Steven's birthdays, showing that he grew normally between the ages of one and eight, but from that point, his growth had stunted. After excusing herself to talk to Greg in the van privately, Connie expresses concern for Steven's growth. Greg is not sure himself why this is happening and how it will resolve, considering Gems do not age at all, but since Steven is half human as well, his properties are unpredictable. Steven overhears the conversation as Greg finishes by saying that they should wait and see how Steven grows.
At the entrance to the barn, Steven tries to hang a birthday banner, but can't do it because the mouth is too high. Amethyst approaches him and tells him that if he stretched his limbs, he would be able to hang the banner. Greg comes up to Steven and gives him his birthday crown and cape, putting him in the barn and closing it to give Steven a surprise later. In the barn, Steven contemplates on whether or not he should shapeshift himself so that he looks older than he is now. Everyone outside yells for Steven to open the door for the surprise and are immediately shocked at Steven's sudden change of physique. Garnet compliments his appearance, but Connie expresses her disbelief and skepticism over his sudden "magical growth spurt". Later, Connie gives Steven a gift box, revealing it to be a pink shirt. He tries it on, but it does not fit well. Pearl, Amethyst, Steven, and Connie play badminton, and Amethyst shoots the racket far away into a tree. Connie tries to retrieve it, but Steven pulls down the branch using his new height. After Connie leaves, Steven's arm shape-shifts into its original form, but Steven forces it back.
In the evening, Steven, Connie, and the Gems are dancing. Garnet changes the song to fit the mood for Steven and Connie to dance alone together. Connie makes joking remarks about Steven's age and new height and tells him that it is funny in a good way that she has to look up to him in a literal sense. Steven becomes uneasy and nervous, excusing himself to take a break. He runs behind the barn, out of sight, to shape-shift back into his original form. Amethyst and Greg witness Steven's shape-shifting and are in shock. Steven shifts back as they both question him. He explains that he needs to stay this way so he can keep a mature appearance towards Connie. Amethyst warns him that he could greatly harm himself if he keeps stretching his form, but Steven dismisses her warning under the excuse that he is half human, so they know nothing about his possible properties. Connie and Steven sit under the stars, pointing towards made-up constellations. Connie expresses her happiness in the prospect of growing up with Steven, and the stress on his body makes him shape-shift into an infant form. He starts crying.
Connie shows Steven to Greg and the Gems as they all share the same feeling of shock. Garnet tries to calm Steven down, but he keeps crying. Greg takes responsibility for his safekeeping and care as a child, as he is the only human parent, and takes Steven for a short drive with Connie to calm him. On the road, Greg is surprised that driving did not calm Steven down as it did before. Greg wants to drop off Connie to her house, but she insists on staying, offering her assistance as the Gems always go on missions, and Greg is usually busy at the car wash. She wants to stay by Steven's side no matter what happens, which seems to calm him down. The following morning, Connie wakes up to see only Steven's shirt on the floor of the tent. She panics and assumes Steven has reverted into a zygote, but goes outside and sees Steven is back to his original form. He reveals how he was aware of what happened when he was an infant and apologizes to her, explaining that he wanted to look and feel older for Connie, but she simply tells him that it is perfectly fine if Steven stays the way he is. Suddenly, she notices that Steven has a facial hair. He shows Greg and the Gems his discovery, impressing them. The iris star closes in on Connie's face as she smiles with relief.
- Peridot (non-speaking cameo)
- Connie Maheswaran
- Greg Universe
- Dogcopter (constellation)
- In CN Asia, this episode was included in the "Turn It Up Loud" Promo where they waited to air the episode a day before Steven's actual birthday, August 14 (since the promo only affects weekends.)
- For Steven's birthday, the Gems made him a Cookie Cat-shaped chocolate and vanilla birthday cake, with a red "1" candle and a blue "4" candle resembling how Garnet was going to tell Steven how Ruby and Sapphire became Crystal Gems.
- Steven's voice when he increases his height is the normal voice of his voice actor, just like in "Garnet's Universe".
- Greg's first meeting with the Crystal Gems occurred when he was 22.
- Greg's photo album shows that Steven has not biologically aged since he was 8.
- "So Many Birthdays" reveals that his physical age is tied to his mental age and/or maturity; when he felt old his body responded in kind. Simply put, Steven's body is only as old as he feels.
- It is canonically confirmed that Greg raised Steven, previously stated in an in-character interview.
- At San Diego Comic-Con 2016's Steven Universe panel, Rebecca Sugar confirmed that Steven's birthday is August 15, the same day Steven Sugar, the inspiration for Steven, was born.
- The album Greg pulled out of the box had the same album cover of Estelle's Shine with the artist instead of being named "Stella", momentarily breaking the fourth wall.
- One of the posters inside Greg's van is titled "Pet Rock" with what appears to be a dog playing a guitar that bears a striking resemblance to K.K. Slider from Nintendo's Animal Crossing franchise.
- When Steven offers Connie Durian Juice, he pulls the juice boxes from the "hammerspace", a relatively common occurrence in cartoons, comics and games where characters are pulling all sorts of things—guns, disguises, matches, bombs, anvils, mallets—from behind their backs or just offscreen.
- The Durian Juice from "An Indirect Kiss" is seen again.
- Steven's Birthday Suit from "So Many Birthdays" is seen again.
- Steven is shown to use his age manipulation powers again. Once again, it was a disaster as in "So Many Birthdays". Except it works in reverse this time, so instead of aging him so old he nearly dies, it ages him backward until he is an infant. He is also shown to have more control over his shape-shifting powers.
- When baby Steven, Connie, and Greg are in the van, the song "Let Me Drive My Van (into Your Heart)" can be heard, as Steven started to like it in "Laser Light Cannon".
- Connie is still training with Pearl, as she was in "Sworn to the Sword".
- Greg and Connie do their "human beings" high five as they did in "We Need to Talk".
- The Peribot can be seen in the background of the barn, foreshadowing the events of "Message Received".
- Steven is later seen wearing the pink shirt again in "Kevin Party".
- From this episode onward, Connie no longer wears her glass frames.
- When Greg shows Connie Steven's birthday pictures a continuity error occurs; Greg never lost his hair until Steven's third birthday, yet in his picture with Rose he is already bald. Matt Burnett explained this error by saying Greg used Rogaine during the first three years of Steven's life.
- At one point when Pearl is tying the large pink bow, her hand is visible while her arm is missing behind the bow.
- When Steven is showing Connie the barn, Greg is still believed to be inside the van. In the next scene, he is shown to be loading the defibrillator out of the back of the van, despite the next scene being only a few frames later.
- In one shot where Greg, Connie, Baby Steven and Amethyst are in the van, Baby Steven is larger than normal.
- When Connie and Steven were stargazing, her head was larger than normal when Steven reassures her that he was okay.
- The banner disappears after Steven shapeshifts the first time.
- Greg's van disappears after Steven shows the gems his facial hair.
- When Steven turns into a baby, his shirt falls off his right shoulder, but after Connie speaks, it's still on his shoulder with no indication of his having moved it himself.
View the episode's transcript here.