Looks like I came in a little late to this discussion, but I think it's an important topic and had to throw in my two cents. When I was in eighth grade I moved to a new school where they had a different testing system for the gifted program. (At that time we had a gifted teacher who taught us for two periods - English and HIstory). I had to wait half the year before I could take the test, so I was in regular classes during that time. I got along with the kids in the regular classes, and was fairly happy there, I suppose. But to be honest, I didn't realize until after I switched to the gifted classes how much I was missing. The class was smaller, and everyone respected each other even if we didn't necessarily get along all the time. That was one thing that was missing from regular classes - the respect. Although I had made friends in the regular classes, they didn't compare to the friendships I made in the new class. It was nice to be able to discuss current events or science, read a classmate's story she had written just for fun, or just show a little bit of curiosity about something without everyone politely asking why I wanted to know all this stuff.
So I guess to answer your question, it is important for a child to have someone to talk to who is on their level. And it's even better if that person is their age.