I friend of mine and his buddy who is a dive master just took me a week and a half ago to a lake for my first dive. Loved it!
Trained me on the equipment, and got me used breathing just a few feet from "shore." When I was ready I took my first swim. When I took my first breaths under water I started to panic, but the DM was calm, patient and made me feel confident enough to do it.
The DM is a SDI instructor. I'm taking his course starting September 6th. Six weeks long, two days a week, two hours a day. One day in class instruction, one day in water training.