Okay - first I'd like to see you get Mom and dad on board and if they are willing- ask your pediatrician to recommend a dietician or nutritionist to get you on an eating program that is healthy.  You don't say how tall you are - but if you are indeed carrying some extra weight - this should concern your doctor - who should:

measure your waist size

Give you your BMI

These 2 numbers will guide the recommendations for how much weight you might need to lose - You can ask mom or dad to start a walking program with you - maybe before or after school or at night after dinner.

Stop eating foods "out of the box" and have 3 -4 servings of fruit daily and a salad (with only a bit of dressing- 2 tsp.) with lunch and dinner.

Go fat free on dairy products - that means non fat milk, yogurt, cheeses - and have 2 servings of dairy daily

In terms of protein - at lunch and dinner have 3-4 ounces of white meat skinless chicken OR fish OR 1/2 cup beans OR an egg white omelet

In terms of "bread servings" - 2 to 3 a day should be enough - that means a cup of high fiber/whole grain cereal, a slice of whole grain bread at lunch and maybe a 1/2 cup of rice OR pasta OR corn at dinner.

You can also look at some of the diet rograms that we evaluate on the site to get more ideas.  I wrote Fat families Thin Families and the book can help you and your family to work on these issues - just remember you want to get to a healthy weight not go extreme.  I also think you will "grow into your hands" so be patient.