I've been on five cruises and 2 Disney cruises. We stopped going on other cruises after the Disney ones. They just do it right, the food, shows, entertainment during dinner, their private island.
Cuba will always be there but your kids will only be a certain age once.
Enjoy never having to cook, just enjoy family meals, walking the deck afterwards, it'll be a good time.
My kids are older, so we go to different countries now but there was a time when a cruise was a great experience for them.
Enroll them in a midnight kids club, my daughter was making pizzas with a girl and we still talk to her and her parents.