Board Thread:General Discussion/@comment-24163511-20140302051112/@comment-24636460-20140305023933

I think "So Many Birthdays" made this pretty clear. Steven is immortal. With his gem he has the power to be any age he wants. Even when he's 200+ he can appear as a child if he wants to based on his state of mind. When he gains more control over his gem, I suspect he'll remain in his adult form forever. Until then he has to be careful because he almost committed suicide just by being in a bad mood, which is pretty intense...