I've had people 20 years younger than me call me "kid", which I always find amusing as it tends to come at the end of an immature rant. That said, I've played with younger kids who are pretty mature and some adults who aren't. Honestly, I'd rather play with a kid than an adult like that. A bit or immaturity is expected in kids (and some of them are actually pretty damn good at games), but when it's an adult, I just roll my eyes.