I am not a doctor or dietitian, but I think it is common knowledge that anyone who needs to lose weight ought to avoid sugar as much as possible. You are to be commended for (1) deciding to lose weight, and (2) having the will power to give up eating and drinking the kinds of things that contain a lot of sugar. I personally don't think you have a thing to worry about if you start consuming sugar again later on, but this is something you should talk about with a doctor or nurse. You ought to be able to talk to the school nurse at your high school. However, once you have lost weight and have become more beautiful, I don't see why you should want to go back to consuming any large amount of sugar in junk foods or other sweetened comestibles. If you can break a bad habit you shouldn't be considering resuming that bad habit at any time in the future. Congratulations! Keep up the good work!
Sugars are important in life. Part of losing weight is 'reducing' the amount of sugars and not completely 'stopping' it. Don't have fizzy drinks, sweets and choclates. You can get sugars from raisins and other healthy food items.