You should be a 13 year kid and go out and be social, play sports and enjoy being young.
If you want to control your weight eat three meals a day consisting of nutritional foods such as lean meats, veg/ fruit, whole grains, legumes, eggs, milk etc. Minimise snack in between meals containing mainly fruit or veg and lean protein. Eat until you are full but not stuffed. You need your protein so I advise getting some in all majors meals
However as I imagine you only basically have a small amount of puppy fat I advised doing the above plus a solid weight training program I advise one of these depending on available equipment:-