My SD was about the same age when we let her- maybe 11yrs? It was summer, and she was embarrassed to have hairy legs. They were pretty bad though tbh- and we kinda stalled as long as we could- but I didn't want her to be embarrassed to wear shorts. So I sat on the side of the tub in shorts with her and showed her how to shave. She tried the creams once- and it just burned too much. Her skin is pretty sensitive though.
I think it's your call- the reason we allowed it was because her legs were pretty hairy and it was dark hair- AND, in the grand scheme of things, it wasn't that big of a deal and made her more comfortable in shorts. Most of her friends were shaving much earlier- as with most things that came along with puberty... so we just took each step as it came and did what made sense for us and her- sometimes we'd both have to compromise to keep the peace. LOL. I do think girls tend to want to grow up too quickly- but, I also know it can be embarrassing if other kids made fun. As kids can do!