My DS will try to play with older kids if we're going to a park or something like that. I tend to redirect or say that those kids came to the park to play with each other, not new kids, etc. I think it's hard to guess what the older kids may be thinking, but I assume they don't want to hang out with DS. I think it would be a different scenario if they were in a group together (mixed ages academic groups or physical groups), but we don't do that usually.
I'm going to try to find gifted kids who are true peers for DS. I'm considering starting an odyssey of the mind league, a Junior FLL, mensa, anything where other kids of similar interests would help DS. But we're pretty busy just with daily life so it's hard. I think in your situation with other HS kids he will get more exposure to older kids and if they're okay with that then I would limit it when it became obvious, or talk to the other boys' moms to have them give the real scoop on what their sons feel about the situation.
