10 years old
It depends on your knowlege of training. If this is your first time, you must know that Chi's are NOT easy to train without a lot of... knowlege of training. So, if you're a first-timer, START EARLY, START EARLY, START EARLY!
When it was first formed.
First you get a license then you advertise.
No, you must first graduate.
CPR and first aid training would be a great place to start.
They mainly focused on their military. They had a brutal training method in which children would start their military training at an early age. The women just stayed home and took care of the kids, we would call them housewifes today
US military advisors were training the ARVNs in April 1956 in Vietnam. There was no "US invasion."