In the upcoming episode, "Steven's Birthday" it is revealed that after having a birthday party at the barn, Steven has some growing up to do? Why? Here is my theory:
It's Steven's birthday.. There HAS to be Connie there, right? It's his best friend, she can't miss it. Also, it's Steven's birthday, if there isn't dancing then you might as well kill me, there'd be no difference.
What if Stevonnie is formed? Stevonnie has the voice and size of a teenager and acts like one. Stevonnie is basically grown up, after becoming Stevonnie again, Steven might realize that he is nothing compared to Stevonnie, therefore he wants to grow up.
Well, that was MY theory, discuss what you think below!