How to lose weight healthy, but also really fast?

I'm not fat, but I am 20 lbs over weight, and I have bulky pars, not m-oobs, but still chub, and I want it to get lost fast, cuz is really annoying me.

I have a slower metabolism, and I have been fat all of my life. I am thirteen, and I want too lose it.

How can a buysy person that dosn't have alot of time for anything, lose weight fast?