Parents won't let me express myself (reasonable question)?

I'm 14.

I live in a rural southern area, most people around here wear boots and jeans. Except my parents, since they are from the city. Nothing wrong with that, I don't have a problem with it, that's just what they choose to wear. But all my friends are country/western type people I guess you could say. Boots, jeans, etc. to everything. Church boots and nice jeans to church. I try to wear my church boots and nice jeans to church, and wear a ponytail, and my parents always criticize me about it. They said I look stupid, like a boy, like a pinhead (whatever the heck that is), and other things like that. They're always trying to get me to wear weird stuff, like dress pants and "ballet flats" to church when every other person there is wearing boots and jeans. When they force me to wear the things I don't want to wear (since I can't go anywhere without their specific approval of everything), I always get weird looks and I'm so uncomfortable. I'm a confident person, but the weird things they make me wear make me feel embarrassed and my friends think I look strange. I have to explain it to them all the time because I want them to understand it is not my choice. I feel that I dress respectfully for church, I would never wear something inappropriate. I think it's the heart and attitude that's important, not what you're wearing.

Am I being unreasonable in how I feel? Any tips on working with them, or thoughts on the matter?

Thanks!!