IMHO, newer divers need a combination of both the coursework and experience. I was certified at 13 with my younger brother. Being junior divers, and with no experienced friends, neither of us dove again after getting our c-cards. About two years ago (hence my profile), I was able to go with a friend on a week-long dive cruise.
I'm not stupid, I took a refresher course before leaving and was very clear with the DM on the cruise that I was a beginner diver despite the date of my c-card. BTW, the DM was very happy that I had taken the refresher.
After a week of diving, I wanted to make sure that I wasn't developing any bad habits and to refine my skills with an experienced diver. So I got my AOW with 15 dives under my belton my next trip and it was the best thing I did in terms of diving in various situations, refining my skills, and curbing bad habits.
Point is, if you are a "first generation" diver among your friends and family, classes are really the best way to go if you are not lucky enough to have anyone to mentor you.