Sister, visit www.PortReviews.com
for about a jillion reviews on Cozumel. In Calica, you should visit Xcaret without a doubt. It is a really cool national park with a great beach, an underground river tube event, great snorkeling, entertainment, a zoo.....tons to do. You won't regret it.
In Cozumel there are so many choices it is hard to decide. It just depends on what you like to do. Read the PortReviews.com site and I am sure you willl come up with a pretty good idea of what you want to do.
Have a great cruise.