Im 14 and want to lose weight?

girls always laugh at my moobs, i have a flabby belly but since i have been trying to ;lose weight my flab doesnt flop over its just there sticking up. i need to flatten it and get a six pack. i got kinda big thighs too. How can i slim my whole body down?. Some girls say i have more moobs than some girls (they think they are degrading me lol). help i hate being fat, i went from hero to zero because i thought i would get muscles by eating more (child belief). i got fat. and deteriorated. help me plz, what exercises should i do?. i know cardio is one. but i cant even last on a treadmill my stamina is very bad.