Hi,
My DD did her grade 3 last Dec at age 11 (shes oldest in her class, others being 10 or 11).
Although I try not to compare, I think its natural that you do, as you want the best for your child(ren). DD also has friends on higher grades at other dance schools, and some that do scholars/associates.
I know that DD is a good dancer, and have been told that she has potential. I can see that she is making progress and always gets good exam scores, but most importantly she is happy and enjoying what she is doing.
Going slower through the grades may ensure that she develops better technique and the strength required to do the harder steps later on.