I want a nose piercing?

I am twelve years old, and for my thirteenth birthday, I want a nose piercing. Just a small little stud, not a ring, I hear they get tangled easily. Anyway, I have thought through why I want a nose piercing and it's not to fit in or be popular. I haven't formally asked my mother but when we see people with nose piercings she scowls. I plan on explaining to her that I will pay for it and all I need is her permission. I've looked up what can happen (infection wise) and how to clean it (with salt water). Also, I want to explain that this will be my ONLY facial piercing. How can I convince her for sure? And also, I heard claire's does not sell very good studs, so should I purchase them at hot topic? Thank you:) P.S, if you're going to tell me I'm too young I understand where you're coming from and this is my decision. Thanks.