Yep, this happened to me with the JACK (furry comic) fandom. I joined when I was 12 and was constantly harassed on the forums and Skype by other, older fans. Making fun of a 13 year old by inviting him to chats/calls then kicking him for no reason other than his age was apparently the funniest damn thing they could possibly imagine. And these were adults, not even like... high school kids.