Asking for a peircing?

For my upcoming birthday in June, I want to get my septum peirced. I really want it done, because it would honestly make me happier. Unfortunately, my parents hate facial peircings. They're very strict and I doubt they will consider me getting one. Unless, I put up a good arguments and hit key points.

I don't know how to ask them, and present the points I have about it. I'm unsure about what to say. My fight could include:

1.) It'd be different. It'd make me happier because I'd look the way I want to look.
2.) I know how to clean it, and I know I'd need to take care of it.
3.) I don't want a huge one, or one with the giant balls on the end. I want a smaller one, that wouldn't point all attention towards my nose.
4.) I'd be able to wear it in school, because the ring pushes up into my nostals easily. They can be hidden in school, and if my parents don't like the way it looks on me, or for special occasions, I could always push my ring up, and keep it hidden.
5.) I have the money to afford it, if they want.

Over all, I really just want a septum peircing. I know where to go, and everything. I don't know how to really ask my parents though and prove my point. It means a lot to me.

I need advice.