Your daughter wants to dye her hair

I was just watching a video totally unrelated to hair dying where a preteen had her hair dyed (some ombré high lights), and I started thinking about if my daughter asked me to dye her hair, at what age I would let her. Feel free to comment, I know the ranges are restrictive and maybe not in line with every ones grouping. I'm sorry I didn't have room to put the option for "when she's mature enough/depends", because I know that would probably be a popular answer as well.