As a matter of fact, the kids that move up often get a favorable reputation among their peers. It's not the end all and be all, but every kid likes to hear his buddies say that he is a good ball player. Call it ego, which I don't think is precisely accurate, but the kids know who the best players are and the better players generally take some pride in that recognition. And kids are kids. Throw them in a new situation with a bunch of new kids and watch the social interaction.
Kids make friends in just under two seconds.
They play up with the big boys, get to do the same stuff the big guys do, talk about the same stuff the older kids do, and might in the end gain some maturity. Along with that, they get twelve or thirteen new friends. Again as a player agent, the friends thing juts doesn't hold true. Kids have a wonderful ability to keep race, sex, looks, ability, and other trivial factors from getting in the way. Now go look at your average adult cocktail party and see the difference.