Gus,
You seem to have a lot of insight into your health for a young man, which I think is great. It's smart to be concerned about this stuff at your age, and I think your first step is to share your concerns with your parents. Finding your best solution can be difficult when you are working through it all by yourself. You and your parents should talk about your concerns, and then make a visit to your pediatrician to make a plan. Take care.
Acknowledging you have a weight problem is an important first step.
Could you ask your parents to take you to the doctor so that you can discuss your weight and take it from there. There should be supports out there to help individuals like yourself. Let your doctor help guide you through this process.
Good luck!