Few things are really worth fighting over
When he was seven our son decided he wanted to get his ear pierced. We hummed and hawed and then decided feckit, some things are worth worrying over, some things aren't.
I've never thought ear-piercing was a topic that merited too much machination, they close up if you change your mind. I'm a feminist which means equal rights for all so if a boy wants to get his ear pierced he has as much right as a girl has. But perhaps most importantly it seemed very healthy that a seven-year-old would want to assert his own taste in a relatively daring way. He wasn't trying to rebel, he just wanted to make a style call. So he got his ear pierced.
He loved it, he got sick of it, it closed up. The whole thing lasted a few months, max. He's never had anything pierced since and he isn't pushed about tattoos, he says wanting to do it and being allowed to do it demystified the whole body décor thing for him. But it was mostly a valuable lesson in parenting because the hardest part about average parenting is knowing when to let children make their own decisions, what is worth arguing over, and what is not.
Micro-managing them into adulthood, so-called Helicopter Parenting, is proven to lead to depression largely one assumes because the child is so squished into doing what the parent wants that their own soul is crushed. That's an extreme but day-to-day we all have to make calls on who decides what. If only it was all as simple as an ear-piercing. In the grand scheme, very few things are worth fighting over.
It's hard to let them take risks but your fear for them can be limiting. Sometimes it is about control, and pride. We want our kids to look, say, achieve, be a certain way because of how it reflects on us. It's a natural, if slightly-weird-when-you-think-about-it motive. (FYI some people: It's one thing to be proud of your child another to brandish your child). But although they are your children they are their own people. So ultimately it's about trust, trusting them and trusting yourself that you did the best you could.