Whatever you do, do NOT run down your child's skills, interests, or anything. As in he's good at x but he's way behind in y. Your instinct is right in this regard. It's tempting, but don't do it.
Especially since your DC can HEAR you and understand it - I remember vividly when I realized that - it had been about me up to that point in terms of fitting in with other parents then. And as Mon says, it becomes about the other parent. Then i realized it was really about him and if i wasn't always his champion no one would be. That's when I stopped talking - if someone asked I would just say simple things, yes he is, or thanks, or what ever was simplest - because not only did I nott want to be denigrating him I also didn't want to be highlighting his out of level skills. I just wanted that to be just him, normal, just who and what he is. These issues come up all the time when little - like the age on the toys - had to explain to DS that it was for choking not brain age (term I got here).
Good news is that it fades as they get older - parents stop focusing on it as intensely although its still an issue - DS is in a gifted school getting some additional stuff in his area of skill and made the mistake of saying something to the middle school teacher and two other parents immediately wanted to know how do you know him, why does he know your kid. And I texted my DH - oops shouldn't have said anything!
DeHe