For your age and height you might want to lose some weight.
You can start by eliminating junk food and snacking when you aren't really hungry. Increase your intake of fruits and vegetables, and be sure to drink 4 glasses of low fat or non fat milk a day.
The best way to lose weight, and keep it off, is to develop healthy eating habits that you can follow for a lifetime.
Weight Watchers offers a very sensible diet plan, and it is fairly easy to follow.
http://www.weightwatchers.com
Dieting should be aimed at a gradual weight loss, only a pound or two a week at most. You need to be sure you are getting adequate nutrition to maintain your growth. Crash diets and fad diets are a definite no-no.
Try exercises designed to tighten up the parts of your body you think are too large, and try to increase your overall activity level. Like dieting, exercise should also be done in moderation.