I know someone who claimed to lose that much over one summer while in high school; although I have no proof. He said he'd eat plain tuna, and I know he worked out. However, he was older than you when it occurred, not age 14. Maybe, start a program with some goals, and ask for help. Change your bad habits. If it is junk food, amend that. If you don't get enough exercise, change that as well. Figure, it will take that much time to incorporate new habits into your daily life to be accustomed to them and accepting without question of a new lifestyle. Be realistic about what is possible. It isn't just losing the weight, it is also keeping it off. So, this is something you'll need to do for the rest of your life to keep the weight off. You might find it easier to learn how to cook and eat more plain foods in order to count calories. If you select boiled chicken breast, it is easy to weight a few grams on a food scale and make a record of the calories. You pick a calorie number for a goal. Plus, you learn how to figure calories burned with your exercise. You can learn about this online or ask your doctor your BMR. There are calculators for that and for calories.