The best answer: Don't WORRY about it... You got a TON of growing up to do. I graduated high school at 6'5" and only 150lbs. Truth is, I'm what they call a "late bloomer" and now, 27 years old, I am still filling-out and increasing weight as I continue to lift weights and live a healthy lifestyle. I'm now 6'7" and 238lbs! Time for you to just eat good foods, VEGGIES! No pop, lean proteins (chicken and tuna) and be happy being a young teenager ! I'm certain there boys or girls for you to be more occupied with in your mind than your weight. Just focus on having fun, being nice to people and creating a positive attitude, before life gets serious for you! Good Luck!
Beauty is in the eyes of the beholder. If you are happy with yourself, thats all that matters!