A Start for a 10 year old
Good point John,
Virtually every club in the country will require that you belong to the AMA (Academy of Model Aeronautics). They are the "Glue" that binds all of us modelers together. More importantly, they provide the insurance that a club will require.
You won't need it right away, but you'll have to join eventually. Dues are less than $60 / year, and that will include both of you.