Yeah I'm not too sure why some state their age randomly when it's irrelevant to whatever they're posting on. Unless they think it's going to make a difference to somebody giving them a villager or something.
I've had somebody pretty much trying to guilt me into giving them a villager for little or nothing only a couple of weeks ago, not sure how old they are but they're school age. I'm sure it can happen with older tbt users too but it seems to be more common amongst the younger people. Just tend to ignore it as I wouldn't like to upset anybody but it can get a little annoying if they won't drop it