I'll bet your smile is getting bigger each day.
If you didn't buy your airfare through RCCL, or make shuttle arrangements through them, you will have to handle your luggage on your own. I would get a porter to do that, it's well worth the tip. You can sign up for your C&A membership on ship or on the internet when you get home. Any cruise credit given is after the cruise is completed. Membership is free and there are great perks, especially after 5 cruises.
Cabin 3521 is more to the bow of the ship and on the port(left)side. Catagory "M" is an inside cabin. If the seas are calm you won't feel movement any where, if you encounter rough seas, your best place is center and lower. Picture yourself on a tetter-totter sitting in the center or on either end.
Hope this helps...