Your body is still developing and you probably just haven't lost all your childhood "pudge". Unless you are severely overweight, I don't think you should worry too much at this point. It's very important to eat and exercise well, while your body is still developing.
Be aware that eating vegetarian can cause your body to be deficient in nutrients that are found primarily in animal products, such as vitamin B12, which is found in eggs, milk, meat, etc; calcium, which is found in dairy - you need at least 3 servings calcium/day, as well as others. You should have a nutritionist help you with a diet that will insure you get the proper nutrition.
Keep exercise!!! :) eat in moderation carbs, starches, fats (white bread, potatoes, avocado Ex.) DRINK LOTS OF WATER! this blog helped me!