Weight Loss?

I'm almost 15, and fairly over weight. (170 lbs) Everyone just says "No, you're just curvy" but I would like to flatten my stomach more. I all have big breast, thighs and butt. I'm 5'6 and quite active, I work out very intensely 3 time a week for 75 mins. I eat fairly healthy, as well. Any tips to tone up or lose weight?