You say that they made it clear that "they rather you didn't." There's a big difference between that and "under no circumstances are you allowed to do this."
I dunno. If it were me, I wouldn't care. It's just a hole, the piercing can be taken out. If it were my daughter, it wouldn't be a big deal to me. As long as she's not doing something harmful to herself, it's all good. The funny thing is though, because I have this sort of attitude, things like that don't really appeal to her.
She's a good kid, and makes intelligent decisions for herself. I trust her.
The only thing I've ever said I wouldn't give permission for is a tattoo. That's not because I'm vehemently opposed to them. It's simply because it's a more permanent thing, and I feel that if she wants one that badly (she doesn't, we were just talking hypotheticals), she can wait till she's of legal age, and get one then. That way, she's taking time to think about it, so the whole decision is on her, and she can't come back to me in a few years and say "why'd you let me get this ugly-ass thing?"
What do you think your parents would say if you went to them and said "despite what you've said, I really want this, and I'm getting it done anyway?" I'd consider that route if I were you. Trust *is* really important.
ETA - after I typed this, I realized, she
is of legal age now, she's 18. I'm obviously stuck in some time warp where she's still 12.
But anyway, the above would have held true when she was 15 or 16.