Hi,
I totally get where you are right not. I was 16 when I started feeling big and being miserable about it. I'm ashamed to say that it took me 10 years to get the confidence to do something about it. Don't wait for the best years of your life to be over before you gain some confidence.
If you want to see results when you are dieting, then look at the scale, rather than your body. Changes in your body week to week are so small that you will hardly notice them happening - but if you keep at it, you will keep shrinking dress sizes without really noticing.
You don't need to starve yourself, the important thing is to make yourself feel like you havent been deprived - I've found that counting calories works for me. Work out how many calories you burn in a day and try to eat around 500 cals less than that (if you go to a gym and do some extra excercise you can eat more) - this way you will lose around a pound a week. By the time you are 20 you will have lost 10 stone if you just lose 1lb a week. Your 20s are so much fun - use that age as your aim to work towards.