In conclusion...

Vegetarianism is good for the environment, and it can, in theory, help your health, and lower risks for many diseases, but you must be careful and really think about how to do this process.  In order to still get your recommended amount of nutrients, you should see a dietitian because they would know a special diet perfect for you.  After you meet with your dietitian, you should get a check-up every so often to make sure your body is getting all the vitamins and minerals it needs.  You also have to think about if this is the best choice for you to choose given everything else in your life, (school, family, friends, peer pressure, homework) will you still have time to think about what you eat when you're in a rush?  As a teenager, your body is growing so you have to take advantage of that now.  If becoming a vegetarian means that you have to deprive yourself of eating things you know are good for you and you like, then maybe it can wait a few years, there's more than enough time to diet. 

Sources:
Gavin, Mary L. Becoming a Vegetarian. September 2006. TeensHealth. 30 November 2008.

Mangels, Reed. Vegetarian Nutrition for Teenagers. 14 May 2003. The Vegetarian Resource Group. 30 November 2008.

Ransohoff, Katie. Vegetarianism in Teens. November 2004. Palo Alto Medical Foundation. 30 November 2008.

"Macronutrients: the Importance of Carbohydrate, Protein and Fat."  What is a Macronutrient?  2008.  Mckinley Heath Center. 1 December 2008