Welcome, New Guy, to sailing.
Taking ASA 101 is a great first step. Also take either the US Power and Sail Squadron or USCG Auxiliary boating safety course for more detailed instruction in the rules of the road and Federal regulations. Two of those will set you on your course to safety.
As for chartering, I just booked my first bareboat charter in the BVI and their bar is alarmingly low for who they allow to skipper a boat.
I think your primary goal should be to keep you and your family safe on the water. The experience needed to charter a boat will naturally follow.
As for what is legally required? Unfortunately almost nothing in most states. As far as I know, only two states require boaters to have some kind of safety course regardless of age. The rest grandfather you in if you're born after a certain date (that date depends on the state). However, both the USPS and USCG courses should also include the state requirements in the tests and you'll be good to go. The state certs do not expire.
Keep in mind, however, whether you take a class or not, you are still responsible for knowing the rules of the road.
Read, ask questions, poke around Sailnet, ask more questions and be safe.