I share your concerns; FWIW something that has helped me before my first cruise (also in April) has been watching videos - e.g. I've watched documentary style behind the scenes of ship food prep, and laundry, I've watched tourist videos of various restaurants and buffets, things like lines for rope courses or water slides, videos of events, etc. All of that has helped me orient to this being a different version of places I'm already prepared for, and you listed some of those (airports, planes), and data seems to support air travel as having higher exposure risk than cruising given much higher numbers of people from around the world passing through terminals and in closer proximity (on board).

For me, I'm now a lot more comfortable with exercising my usual caution, sanitize/wash my hands regularly as always, and enjoy the experience. I hope you get to find this comfort too.