You found an instructor, took a basic class…now what? Practice what you learned? Work on your basic skills, make trigger control a habit, work on your marksmanship. Get comfortable with your gun, how to take it apart, how to clean it…
Then…consider an advance class. How soon? That depends on you. If you are consistent, and comfortable within a few months, you are ready to go to the next level. If not, you might need a little longer. But, what next class to take? That depends on what you want to do with your shooting. If you are a plinker, maybe an advance pistol, or a beginning rifle class would be fun.
If you are looking for self defense there are more options. You can look for an NRA Personal Protection in the Home class that will help you understand the need for a safe room and how to protect yourself and your family if danger comes through the door or window. You could look at a NRA Personal Protection Outside the Home class. You could consider a Concealed Carry course offered by local instructors, or even a Combat Focused Shooting class, developed by Rob Pincus, that is becoming quite popular (although they may be harder to find depending on your area, but more and more instructors are getting certified to teach this program).
The key is to keep learning and keep practicing. When do we stop learning? When we stop breathing. Until then, there is always something new!