How to tighten the skin and lose weight?

i am 15 years old. 5’3". and like 210 pounds. i am very over weight.
how can i lose weight healthy and tighten my loose and flabby skin.
i would like to get down to 130 or somewhere around there. my problem is i have like no will power to do it. i have tried many things but i never stick to it. please someone help me.

Also i am a very picky eater.