Filmmaking / Directing : I need to direct a child, what age is a good age that will follow instruction? by Angela Houston

Hello! I'm a 17-year-old filmmaker from anthem Arizona, I have had an idea for a script for a very long time which involves a young child talking to his dad, who is an astronaut. Their lines are simple such as "where are you going daddy" and "can I come with". What age is a good age range that is young enough to be in grade school, but doesn't look too old? Thank you!