First and foremost, you're beautiful and don't let anyone tell you otherwise! I once heard it said "Nobody can make you feel inferior without your consent" - Eleanor Roosevelt
Kids can be so cruel at that age, so don't let them be the judge of whether you are overweight. Ask your doctor whether you are a healthy weight for your age and height, or if you're truly overweight. If you are overweight and want to lose weight, make sure you do it slowly and in a healthy way. Avoid any fad diets that tell you to focus on only one kind of food or promise overnight results.
Make small changes to your eating habits you think you can stick with, rather than going on some super-restrictive diet that you will eventually quit.
For example, if you love soda, and you try to restrict it, you might be able to do it for a few weeks, then one day slip up and then feel like you've failed on your "diet", and then go back to eating like before. However, if instead you cut your soda intake in half, you won't feel deprived, and you'll also discover other drinks you like. And you'll be able to stick with that change. Same goes for sweets or other treats: Cut back, but don't restrict them entirely, so that you can stick with it. Moderation is key.
Eat lots of fruits and vegetables. Find fruits & veggies in every color of the rainbow to get a variety of nutrients.
Choose whole grains (whole wheat bread, oatmeal, brown rice etc.) instead of white breads. The extra fiber keeps you full longer so you don't get hungry. Fruit is also packed with fiber, which helps you stay full.
Choose lean means (meat without a lot of fat), such as chicken breast, lean beef. You can also get protein from beans and eggs.
Avoid "fried" as frying adds lots of fat to your food. Instead choose foods that are "baked, broiled, grilled, roasted, or steamed"
Avoid fast food as much as possible, but if you have to eat in a fast food restaurant, opt for "grilled" chicken over "fried". Skip the mayo & bacon. Ask if they will swap out the fries for a fruit cup.
Salads are a good option, but watch out for the dressing. Some salad dressing packets contain as much fat as a cheeseburger. As a general rule, dressings that are creamy (Caesar Ranch, Thousand Island) contain more fat than dressings that are clearer (balsamic vinagrette, low-fat itallian). Choose a low-fat dressing.
Also, try to increase your physical activity. Do you like to play sports? Maybe you enjoy riding a bike or taking walks. Try to find something active you enjoy doing. Sports can also be a great place to make new friends.
By eating healthy and adding activity, you will be taking in fewer calories, and burning more calories through exercise. You may find you have more energy during the day.
Best of luck to you.