Alpha.. I am a "newbie" too. I have completed my class, and thanks to an aggressive instructor, I also have completed a very high stress set of pool sessions. I am a lifeguard, and serve as a safety swimmer for our swat/maritime training sessions.. These guys here are telling you gospel. One thing, if you havent done it yet that you must learn as well is how to equalize your ears. On one of our training days, before my scuba class, I had to retrieve a scuba weight from the bottome of a 20' deep pool. I did a dive from the surface with my aqua sphere goggle on. By the time I passed 15' I felt like an elephant was standing on my head. At 20', I got a real live, first in my life case of vertigo. Once up, I had developed a nice "sinus block" (you will learn how to avoid this in your first day or so of scuba class). I had sinus pain for about 3 days, and Im not talking about a little pain. Proper equalization is easy once an instructor shows you how and when to do it.
If you really want to get a head start on your class, start swimming. Alot. Do 50 foot or more underwater swims at about 4-6 feet deep. Practice exhaling as you come up. Find out which open water program your instructors will be using (Padi, Naui, etc) and go online and start practicing working the dive tables.. That is what gave me the hardest time of anything in MY class. The math, and the Naui tables.. once I got it, it was easy, but I was confused at first.
Your instructor or dive shop should let you buy your course materials well in advance. I really enjoyed the Naui video, it matched my workbook and really helped. I even listened to the CDs in my car as I drove to work and back..
oh yea, SWIM. Our class had several students that showed up not able to do a freestyle swim for the required 200 yards, much less the required 50 foot underwater swim.
Hope this helps you see what is ahead.. and like they said.. no compressed air at all until you have an instructor looking at you by the pool.
I had a ball in my class, by the way, cant wait for the gulf to straighten up in Florida, so I can make my checkout dives.
Shane in Baton Rouge.