Me, my parents and my sister went for a cruise on the Disney Cruise Line. We went to the Bahamas and to Disney's own island right near the Bahamas. I was about 18 or so years old, and I found it a little boring actually. They had stuff for the adults, for the little kids, and for the teeny boppers, but they didn't have really anything for the people in between. Some of it was nice though, like looking out over the ocean as we sailed, and going snorkling on Disney's island.
One thing about the Disney Cruiseline is they feed you like there's no tomorrow! A big buffet breakfast and lunch, and all day bar by the pool that serves ice cream, chicken tenders, french fries, and various drinks (food is included, drinks are extra) a dinner in one of four fancy resaurants on the ship that you must dress for, and hors deurves (sp?) at night. You couldn't go hungry on that ship, it was plain impossible!
I hope you have lots of fun on your cruise!