How do I convince my parents to get a belly on ring?

I WANT ONE SOOOO BAD. I asked a few months ago and got rejected. /: So like a CRAP load of my friends are getting it donneee, and even my ex-best friend whose mom and dad ARE SOOOOO FREAKIN STRICTTT let her do it. Wtf. I'm 13. And I'm not gonna be walkin around the mall with my shirt pulled up, seriously. I know they thinkk it's to "y" or somethinq, but seriously. Come on. Help?