SPG,
Although my DS doesn't have a "best friend" he has many friends. He doesn't really care for kids his own age and he gets along great with the older kids. He's extremely personable and having people to pal with shouldn't be an issue. When asked about skipping and all the moving he does over the course of his school day, he's fine with it. He wants to be in classes that are exciting and interesting. It never occurs to him to question his own age in comparison to the other kids in his classes, it just doesn't come up.
Part of his willingness to fit in with all ages comes from growing up in a household of ever changing age groups. Whenever we get a new child in, the rest of the kids help them fit. So DS will play monsters with the 3 and 4 yo's then move on to play Bakugan with the 13 yo. He also spends time on his own everyday, his choice. He kind of understands what each group brings to the table and uses them to meet his various needs.
