B.K.
Well, unlike the previous poster Elizabeth, I am not going to laugh out loud or be sad that you are thinking about this and questioning this. I think it's a great question and a great discussion topic! I would not consider mocking someone who uses this site for what it is designed for -- a forum for discussion.
That said, as a mom of a 21-year-old and 11-year-old (both girls) I've been through this and will go through it again. My older daughter was the one who brought it up to me and it was just before junior high I think. At that time, I thought she was young but she wanted to do this and other girls were shaving so no big deal to me. We started with an electric/battery shaver. That way no slicing the legs up with razor (and for underarms, which seemed to need shaving earlier than the legs.) She was the one who wanted to use a regular razor and she tried several over the years and settled on a sensor excel razor (a men's razor but it works really great) and that's what she uses to this day. My younger daughter has talked about shaving her legs, but nobody really does yet in school and so we chat about it but then she drops it. I'm thinking next summer or the following she'll want to shave. She's not very hairy. My older daughter was. Some people have more hair on their legs and it makes them self conscious and want to shave earlier.
Anyway, I think your daughter is a little young yet, but before you know it she'll be talking about it and you'll have some ideas for her. :-)
My mom also didn't want me to shave until high school, but I wanted to and sneaked in shaving when I was in junior high. It would have been much nicer to have my mom on my side and not as an adversary. And so shaving was one battle I wasn't going to fight with my daughter. It was an open discussion and I helped her, which is probably what you're going to do.