Hi Litto-Roxxi
We all tend to compare ourselves to others too often and yet we forget how wondefully made we are. From your question I think you are a very mature 11 year old and not only that, you are sensible and active. You cheerlead, dance, swim, play net ball and even get backy's :-) Enjoy your life growing up. You sound happy, be a good student, a loving daughter, a loyal, caring and trustworthy person and above all have Fun! This is what is important right now.
I'm glad you are thinking about diet and exercise, the best advice I can give you is to keep up your physical activities at your age you need about 1 hour every day of physical activity. When it comes to food, eat lots of fruits and vegetables. I'm cheering for you Litto-Roxxi!
Kenn Kihiu
http://www.dancexfitness.com