i am 11 and 6.1 stones. I would say the average weight for an 11 year old is around 6 stone but don't worry about your weight because you are still growing and its really quite unpredictable.
Anyway, try this website
http://www.nhlbisupport.com/bmi
hope i helped xx xx
4 stone
6 stone
about 4 to 5 stone
22 stone
around 15-16 stone
13 stone
A stone is equal to 14 pounds. Therefore, a six year old should weigh about 4 stones or 56 pounds.
Exactly 6 stone 5 pounds.
50 stone
Roughly 10 stone
9 stone
11-12 stone