We have the same situation. DS8 has friends of many ages, but socially he fits best if kids 1-3 years older than he is are playing. We're homeschooling, so that makes this sort of fluidity easier to find and means that his age is really a non-issue. And he is big for his age. But I think there are plenty of GT kids for whom older kids are a better social fit than kids their own age.

Kriston