This is off topic from th OP question, but related to HK's and aeh's thougnts. I don't think it ever stops, honestly. As a young physician, I was frequently asked about my age, gently 'accused' of being only a student when I was actually an attending, etc. And I am not accelerated, nor do I look young for my age- I looked and certainly felt every long year of that training. I think it is just a tactic used subconsciously (or not) to control, intimidate, or express feelings of inferiority, a response to feeling threatened. I won't even start with the comments about me being a nurse, as that's a separate topic altogether (though just as frustrating).
Like many things of this sort, I think it's best to not take it personally and develop a standard response that is polite but clearly settles things, however you wish to respond, and help your kid do so as well.
