I thought it was a bit of filler episode at first. But it did delve into Steven's anxiety about being constantly treated like 'Classic' Steven by the Gems. He wants to grow up so badly, but he feels he's being held back by time and the perceptions of others.
His tantrum at one point could be construed as the usual behaviour of a petulent teenager lashing out at those perceptions. But it could also make us believe that he's about to lose it and turn to the Dark Side, which has been alluded to through out the season.
I feel like, some people thought it would be like Three Gems and A baby but we were never given much reason to think that that I'm aware of. plus it makes sense given the way the rest of the series episodes before that were headed, and some people's dislike of older Steven feeling like it needed to be addressed which I do think it did. everyone grows up, glad at least a few Cartoon Characters have as well at least soemwhat.