Congrats on turning 21. I turned 21 last week and took my class 2 days later. Mine was a written test then a shooting test. The written test was simple and afterwards we went over it as a class to make sure nobody failed. I think they did this part that way because in Alaska you do not need a ccl so they don't want to fail somebody unless they do a terrible job.
The shooting part was fun for me. It was an all day thing. They taught us all the drills, corrected are shooting techniques, and taught us a bunch of information. The shooting part just takes practice. It was not to hard for me though.
It was 12 rounds at 3 yards, 7 yards and 15 yards. For each part we shot 6 at a time, performed a tactical reload then shot our next 6. I passed. I think one person in the class of 21 failed it.
I think just practicing your shooting and get update on local laws and you should be fine.
I found this on google for you by the way. I am assuming you are from Texas so hopefully this applys to you and maybe helps you out?