RE: Joining a club
You aren't going to know the specific answers to these questions until you approach members of the club that you want to join and ask them.
No, there is no age limit but some clubs limit the number of members they take in. It costs an annual AMA membership and whatever annual dues the club requires. There is usually no charge during the year to fly after you have joined the club unless you are entering an organized event such as a fun-fly or a pylon race.
It is highly recommended that your first plane be a .40 size high-wing trainer type aircraft. This will give you the best chance for success.