Dieting is not a good idea while you are still growing.  A small shift in lifestyle may improve your self-confidence. 

Try participating in a team sport such as netball, football, hockey... where you can feel needed as part of a team, lose weight, get fitter, and feel good about yourself. Sport gives you a buzz, a buzz to perform, and to achieve. Exercise speeds up the metabolism, allowing you to eat loads without gaining any weight at all. Don't go mad, just walk instead of catching the bus, or run to the post-box rather than walking. Taking a bit more exercise is what is recommended for people of all ages, especially if they haven't got help from a doctor or dietician when planning a diet. If you already take a lot of exercise, then it is quite likely that you are putting on a lot of muscle, and so that is probably why you weigh more than your friends. Exercise is the key to losing weight. Make sure that you get plenty to eat after sport, and make sure you get all the nutrients and variety you need in your diet.

All girls put on weight in puberty anyway. It'll be this fat that will protect babies when we are pregnant. Loads of girls tend to think they're fat during puberty, and this is why anorexia is becoming so high in teenage girls, and is increasing in boys too. Just remember that you aren't fat, and more importantly, be confident in yourself and in who you are.

 Rather than dieting change what you eat instead of change how much you eat. Substitute unhealthy food, or modify the way that you prepare it (e.g.: poaching eggs rather than frying them). Make sure you get enough from all food groups. People who diet tend to become salad freaks, and that means that they get very little protein or oils, which is essential to be healthy, even veggies don't live on salad. 

 REMEMBER -

1.       Crash dieting is bad news. Lose weight very gradually. Also, keep note on how much you lose each week, and make sure it isn't drastic amounts.

  2.       Never regret what you've eaten, think about it before hand, or you are in high risk of it developing into Bulimia.