I'm really self conscious and I only like one thing about my body, my flat stomach. I feel like getting a navel piercing will show off my one good thing. My mom thinks any body modification is a sign of a whore. But she'll never see it because i'm not allowed to wear bikinis but I wear crop tops. Should I get one or wait until i'm older? do I get it without her consent?
You would get one or not get one because you want to.
If you wait until you're 18 you won't need her consent.
When you move out, she isn't paying for your food clothes and housing, when you pay your own bills, when you're an adult you can do it. For now, you're under her care, her authority and you kinda gotta listen.