You will have a GREAT cruise!
I agree with all that has been said. There is no legal requirement to change a name after the wedding. My daughter chose not to do it. Others hyphenate the name. In a couple of cases I know the couple chose to exchange last names! But in fact it is legal to use any last name you choose as your legal name as long as there is no intent to defraud. Stick with the current passport for this trip, then make the change when there is no time stress.
It is very smart to be flying into Ft. Lauderdale the day before. This is a great way to avoid stress and make it much more likely that you arrive in good time with your luggage intact.
(But not perfect -- when you travel stuff happens. Once we had an overnight pre cruise in FLL. Our plane could not land in HOU due to high winds, and after multiple diversions and misadventures we flew to Orlando about midnight and rented a car to drive to FLL. Our luggage was probably in Austin by then, so my wife boarded the ship carrying four bags from Target as our luggage! The itinerary did not put us into a port with air connections until Aruba on the third day of the cruise so it was an interesting experience. The cruise line was incredibly helpful, even gave me a free tux rental! Check out our adventure, and the GREAT cruise we had anyhow, at The Halls Southern Caribbean Cruise
. Moral of the story -- be sure all the IMPORTANT stuff is in your carryon!)
When we were about your age (a long time ago) we were on a cruise to Alaska largely populated with an older crowd. We wound up seated at a table with two gray haired grandmas. It was absolutely delightful, they were wonderful ladies, and we exchanged Christmas cards for years afterward. I will say that after midnight the night club was populated only by us and one other couple from Minnesota. We got the band to alternate rock n roll for us and polkas for them and had a ball!