Chubby cheeks? How to get rid!?

Okay, I'm 12 year old, only just started adolescence and have a really ROUND face, ( O < that round ) and it's mainly my cheeks. I'm not fat, I don't even fit into size 6, and normally get age 9-10/ 10-11 but if you only saw my face, you'd think I'd be really chubby? So is it "puppy fat" or just fat!? And how to get rid of it!? :/ its really getting me down