AITA for continuing to weight train even though my parents forbid it?

Y’all, this is the stupidest situation I’ve ever been in and I need the internet to weigh in because I have no idea who is the AH at this point.

I (16F) have always been really big for my age. They tested me to make sure I didn’t have a medical issue because it was so freaky, but turns out nothing is wrong. I’m just really tall and built. I’ve been teased about it my whole life but I like it now. My parents do not. They worry about me not fitting in and they get really upset when people confuse me for a boy (which happened a lot before boobs). So, my mom has always had me wear really obviously girly clothes, I have to keep long hair, and they’ve always pushed me towards really girly things. I think they’re afraid I might be trans or at least people will treat me badly thinking that I am. It’s not great, but it’s always been more trouble to not go along with it.

I started working out over the last year and I really like weight lifting. I must have good genes for it, because I’ve made a lot of progress. The problem is that my muscles are bulking enough to be noticeable now and my parents think it’s going to get me bullied for being too masculine, so they said I have to stop. My mom suggested jogging or yoga instead. I’m going to yoga, but I miss my weight workouts. So, I asked the coach that teaches my health class if I could come in early and use the school’s weight room. I’ve been doing that for a month, but my parents found out about it this week from one of my teachers. They said I disobeyed them and went behind their back and I’m grounded. I said it was really stupid that I can’t workout the way that I like and they can’t stop me. My mom said I’ll thank them when I want to start dating. I’m doing pushups out of spite and my dad says that it’s good that I want to exercise but I’m being disrespectful.