Do you think 12 years old is too young to wear 3 inch heels?

My 12 year old bought these 3 inch heels a month ago. They're not stiletto, they're wide but thin, and are criss-crossed with thin black straps, no platform. She's worn them to a dance and 2 formal plays her cl went to. I tried to get her to buy a simple pair of flats or at least a lower heel but she refused. According to her, half the girls showed up in heels as high or higher than hers. However all her friends wore flats. When she came home from the dance, she had several blisters, one which was bleeding, and said her feet hurt like heck. Yet she still wants to wear them. What should I do? She bought them with her own money, so I guess she has a right to wear them when she wants to. It's her feet, after all. But still, I'm a little worried. She looks so grown up in them, I swear she could p for a short 16 year old. And that's not the kind of image I want her to have, because quite honestly heels are for 16 year olds only. Should I buy her a pair of flats and tell her to wear them instead of the heels, or just let it go? I guess it could be worse than 3 inches.