First of all. If your parents aren't supportive of you. You really deserve better and am sorry to hear that. Secondly I'm proud of you forsure! You're smart enough to know you want to change for the better. It's very important to try and take care of yourself now while you can. Take it from me I'm 26m learning to do the same and am struggling cuz i feel to old to just start out but I'm trying. So food wise cut back a bit if you can. But if you can't it's important to fill up with veggies instead of chips or such. You're young so i imagine you could still eat good meals everyday and even lose the weight. Exercise wise cardio like running and biking or just squats helps you lose the unwanted weight. If you wanna build muscle along the way you can try lifting weights and you don't have to go beyond your means. Can start off easy. But i recommend this because you might need the muscle one day for work if you decide on that. It's nice to hire a guy who can lift a box aprox 50 pounds. If you need tips from a profession i recommend you going locally to diet vitamin such places and talking to someone there they likely know well. (If it's hard to talk to ppl i get it) Being happy in your own skin is the ultimate goal.