Ages

I wonder how many people like me find many of these American Girl movies somewhat spoiled by using actors and actresses who are much older than their characters. I mean Sidney Fulmer is an excellent young actress but is 4 years older than her character, she is completely unbelievable as a nine year old, even her voice sounds older. The same also applied to the Molly film, she celebrated her tenth birthday but was played by a 13 year old. I'm sure there are many talented 9 and 10 year old actors and actresses out there who could play the roles just as well. I mean Samantha and Kit were both played by actresses who were of the right age so why not the rest?