One thing I don't see here, is what you want to DO! Are you interested in walking/hiking/biking, or just sitting somewhere while you eat & drink? The cruise ship is just transportation, unless the shows excite you. Sure, there's lots of good food, but nothing is free.
DW & I decide on where we want to go, based on what we want to do when we arrive. In Japan, we toured ancient castles. In Australia, we toured wineries. In Turkey, we took cooking classes. And we didn't pay for the cruise lines for those activities, as it's easy to set them up yourself. As a first-time cruiser, you probably just want to "enjoy the ride," but keep an eye out for what you can do on future cruises!