The key is to develop healthy eating habits. Right now you're young, and your body can process all that junk very easily. You don't have the toxic accumulations of a 45-year-old either. It's okay to eat fun sometimes, and enjoy life, but you should continue to put a limit on how much junk food you will consume, and cleanse and detoxify on a regular basis. You have the jump on many people b/c you are starting young, and it will pay off in the end when you don't see the doctor hardly ever, you look young and healthy for your age at any age, you don't get the three major diseases that have become EPIDEMIC in our country: diabetes, obesity, and cancer, and you have more energy than most people you know in your peer group.
The body is like a car, and like a car it needs MAINTENANCE! So be mindful of what kind of fuel you are using to run it, the better the fuel the better the performance!