Do i get a plastic surgery?

I am 16, tall, dark and cute. problem is my boobs are beginning to sag due to constant weight loss and gain, i have stretch marks in and on all the wrong places. i've got love handles. my **** isn't round, it's long straight(can't really describe.. tilted downwards) i'm presently fat but i'm scared to lose weight because i do not know what will become of my boobs if i lose weight cos the only thing holding it up now is fat and if those fats leave...... i've never had sex and i really want my 1st time to be special but i want to look good naked so that i don't lack confidence. i want a breast and buttocks augmentation, a lipo and a laser stretch mark remover. i want to know the approximated cost for these and i need advice on which surgery type conceals scars the most. thanks.