Hello and congratulations. You are going to have a great time!! I would call the TA who did the booking and if there is no help there, call up Royal Caribbean and find someone to talk with there. If I am not mistaken, they may be able to take care of it on the ship as well. I would try to fix it before I arrived though if possible. Take plenty of pictures so you can take a break from all the talking about how great the cruise was and just show folks the pictures!!! LOL!!
I still remember our first cruise like it was yesterday! It has been a number of years since I have been to Nassau so I will pass on any information here as mine would not be up to date. As someone has said, arrive by noon and then you will be onboard and your adventure will start. Have a great time.