M.R.
Go to a salon! For multiple reasons -
1) Its your big cruise! Make it special, make it professional, you'll glow! :) Actually, try going to a salon to get your arms/legs waxed first, and see how you feel about the experience. See how your body/skin reacts to it. If all goes well, go for the full thing 2 or so days before you actually leave for your cruise.
2) Since you haven't tried it before yourself, waxing bikini area and even arms and legs can be tiresome and you may end up bruising your skin here and there. If you've regularly used wax before, then it may be another thing
3) Salon assistants have seen it all, and people of all ages, sizes, coloring, skin textures, etc etc (u get the picture) get it done. Don't worry about what they'd think or see. If you feel like gold, then you feel like gold! :))
4) If you are interested in trying hair-removal by yourself, Sally Hansen and Nair are two good brands. I used them a couple of times and found them decently effective. Just follow their instructions on how to very properly. Experiment first before trying it just before your vacation.
Have a wonderful cruise! :)