My mom made me wait until I went to middle school, so around 12 years old I think. That was after begging and getting her to reduce it from the original rule of 13. I was pale with blond hair, but it was thick. All the other girls had nice smooth legs, and I had albino woolies. It sucked.
When my sister started cheerleading in 5th grade, my mom asked my opinion about if she'd been too harsh and if she should let my sister shave earlier than she chose to let me. I said without a doubt, she had to let her shave if she was going to be in front of the whole school in a short skirt. She finally relented and lifted the shaving ban on her when my sister called her at work in years because of something another girl said at practice. I wound up helping her shave her legs the first time. It was a fun bonding moment and we still laugh about it now, 20 years later. My mom has apologized to us both for being so rigid over something so silly.
My kids also have pale skin and fair hair, but when they asked to remove the hair I showed them how to do it. I isn't make a big deal about it. I think my oldest was 9 and my youngest was 8 when they started. Both of them are still good students, they didn't turn to drugs or prostitution, and no one has lost a leg, so I think it was an okay decision