DS is accelerated from 5th to 7th in math and literature, has been in that pattern for two years now. He gets along really well with the older classmates, they will say hi to him and chat with him at school events, teacher says they treat him like one of them, etc. His buddies are in 5th, though. In fact, that's part of the reason he's not been whole-grade accelerated. He seems to like having age mate friends (but is also very comfortable with older kids, seems a good mix).