If she is very hairy, and if she is getting picked on, you absolutely have to let her start. I started waxing my daughter's unibrown in second grade, because she came home crying due to girls making fun of her. I was reluctant at first, and gave her all the usual tips about disregarding mean comments, those girls not being her real friends, etc., but it really started to have an effect on her feelings about herself. And THAT is not worth it. I made sure it was just the center part, and even now that she is 12 I still make sure it's natural looking, not polished like an older teen or adult would want. She just started asking about the legs when she was ten, and I put it off again at first. She didn't want to shave it though, and asked me to wax it. I use Moom sugaring paste, which doesn't really pull like the regular wax. I did it once in the summer the last two years and she didn't care about gym class or anything during the school year. The other day she asked me to teach her how to do it herself. After one strip she told me to let her do it, and she finished her legs (lower only of course) by herself. My niece who is almost 13 came over and asked me to do it for her (with my sister's blessing of course), but ended up learning to do it herself as well. My daughter had never shaved, even though I offered to teach her, but my niece thought it was much easier.
Anyway...a lot of rambling for you. Go ahead and let her. Girls can be especially cruel nowadays...way rougher then when we were kids.