Texascat---you did one hell of a job editing that post!!! Girl, are you on the "shots" again??? I'm sorry about your trip truly, but I think you will have a great time in Cozumel. There's not much night life there though--did you know that??? You can get certified in Cancun, or stay there and take a day trip to Cozemel for the certification. We have been to Cancun every year like forever...it's my son's favorite place to go. Mega things to do--nite life,good cheap food,great hotels w/ lots of activities,beautiful ocean,decent but not great snorkling. People, people, people--definitely not what you would find in AC. How long do you have to vacation? Don't stress--any vacation is better than none--and you have a wonderful reason to be doing it--a 20th anniversary!!!! Congratulations!!! Don't worry about the water when you are getting certified--relax, and enjoy all the wonderful things you are going to see--it's not claustrophobia-- it's 3/4ths of the world that is now open to you. Be happy!!!!