Is six stone overweight

It depends how tall you are. I'm 14 yrs old - 5 feet 7 inches and 7.55 stones... I'm a bit underweight. You might be underweight too, unless you are very small in height.

Weight is related to height and body composition rather than age. For more information and to view the height/weight chart for children, see the page link, further down this page, listed under Related Questions.