Hi, Hanna ...
A little late checking in here. Donna's and Kuki's answers are right on.
What we do is bring ONE bottle of water each onboard and fill it up from the tap in the bathroom. Ships' water is probably cleaner than what comes out of our taps at home.
Do NOT lose the beach towel the ship provides. There is a hefty charge for lost towels. You can also take more than one per person.
Of course you're nervous and excited. A whole new adventure before you. ENJOY !!! And if we can answer any more questions, just holler!
pamda -- CM First-Time Cruisers Editor