AITA for allowing my 11 year old daughter to get a nose ring despite my ex-husband's intense disapproval?

UPDATE: first off, I didn't provide any context because it was 1:am and I was ready to pass out for work the next day. My daughter is not 11 as some of you believed and neither was this her first piercing. She had her ears pierced at 6, her septum at 8, and both ring and bar nose piercings at 9. She is very good at taking care of them and recently asked for a rhino ring (a ring nose ring that T's across the tip of the nose) which I permitted her to get. I explained to her that while we're divorced, he may think this is untoward and to be prepared. She said she's ok with him being upset as long as she's able to get it. However, she also wanted to wait until we're able to do it without him knowing and messing up her piercing. She thinks that if he sees it he'll try to bully her into taking it out and she doesn't want to risk that. That was all well and good until he found out and sent her pictures of ring noses being infected. She didn't like that and went on the defensive which led to a huge fight. I'm so confused and upset about this I'm not sure what to do or how to handle this properly. I'm so sorry if any of you thought this was the situation. I'm honestly extremely thankful for your input and I'm sorry if I didn't respond. Some of you are right and some of you are wrong. I'm not going to specify who is who however. I will say that some of you, like the ones saying she shouldn't have it because it's not common are blatant bullies.<br> <br>tl;dr: My daughter has had piercings since she was 6. Her father is against this and when he found out her latest piercing he sent her pictures of infected piercings which led to a huge fight.