You are a 10 year old girl and 8 stone half you obese?

No, you are not obese.

According to the World Health Organization, a child is considered obese when their weight is more than 20% above the average weight for their age and height. For a 10-year-old girl, the average weight is around 7 stone 12 pounds. This means that a 10-year-old girl who weighs 8 stone 7 pounds would be considered obese.