13u. He's still only 11 (12 in Nov) but went from the small field to the big field in August playing in 14u. Best decision I ever made. He's a catcher so maybe it would have been different if he played somewhere else - certainly if he pitched. But as a receiver, I'm glad I walked him past 13u. Pitchers actually throw 90% over the plate instead of bouncing their pitches in the dirt 10' in front of the plate, they hold runners better so he has a chance to throw them out, and there appears to be less drama - more dugout fun and less 'can I play on this field' concerns. Curious about the experiences other catching families had on the big field jump.
I'm a big proponent of raising the bar and taking every advantage of being able to play at a higher level as I feel it can only be a positive. By doing so, you learn whether he can succeed at a higher level or not. If he succeeds, then you look for more opportunities to raise the bar. However, I would not "push" him to these levels as it should be your son's decision that he can enjoy what he wants to do. The players that really succeed are those who have the drive to push themselves where they want to go. And your support in helping him achieve what he wants will go a long way towards his success.