I am a newbie as well and did the same thing after receiving certification. Two things that I would suggest: First, be up front with your divemasters, let them know that you are new and that you would like to be either buddied with them or tell them you'd appreciate them keeping their eye on you. They have been very accomodating to me in this respect. Second, be sure that others in your dive group know that this is your first time out as a OW diver. You'll MOSTLY get great support, there is always someone that had Aqua-Lung on their umbilical cord at birth, but that happens in any sport. I would also suggest trying out one of the local dive operators not associated with the cruise line. Some will do small groups and it is a real change from the cruise ship operators, but I had very good luck with the operators used by Holland-American on our cruises. The local operators are a little more personal and you tend to get a little more of the local flavor. I would suggest that you do this on one of the longer port stays. Either way, you'll have a great time. Remember to dive in your limits and follow instruction, it will be everything you've expected.