I agree with the idea of having a few dives under your belt before taking the AOW course. It gave us a chance to use what we learned in OW, and develop a list of things we had to work on to improve our skills. When we took the AOW, I had a short list of personal goals that I wanted to accomplish via the course.
For example: My bouyancy was reasonably good, but I was able to really get it fine tuned via the peak performance bouyancy specialty. A lot of divers told me that one day, around 25 dives, I would "get it," but, under the supervision of an instructor, I was able to dial in to that weightless feeling and register it in my aging mind for future dives. I was thrilled during the rest of our dives when I was able to find the sweet spot again and again. In retrospect, I don't think I could have accomplished the same thing going to AOW straight out of OW.
We learn about task loading, but the more I dive, the more I understand the true meaning of the term. Remember: When you're up to your a-- in alligators, it's difficult to remember that your initial objective was to drain the swamp.
The more you improve your skills, the less you have to think about them; and the more you'll enjoy your diving. There's also a school of thought that says you should take AOW immediately after OW, so you don't develop bad habits. Just remember that everyone is different, and do what works for you.
On another note: More and more places are prohibiting knives (including Cozumel). Get yourself a pair of EMT shears, and maybe a small line cutter, and forget the knife.