It depends on the girl and the legs in question. I certainly wouldn't force a girl to shave her legs if she doesn't want to do it, no matter what the hair looks like. Listen, if your ten year old has legs that get mistaken for Sean Connery's chest, but she doesn't care - then why are you stressing about it? Clearly, she is settled enough with herself and her body that she couldn't care less what her friends or the other kids on the playground are saying. Why instill a sense of shame for something she isn't ashamed about? On the flip side, if your ten year old is sobbing every night because her legs, which sport only a fine layer of down, are causing unending teasing and mockery during gym class, bring on the razor. Or if that seems a bit much, maybe a lesson in self-esteem. Point is, there's no right or wrong time, and there's certainly not any standard "Thou shalt shave thy legs at age 12, and not before." It's very much dependent on the situation, the girl, and the culture she's in.