I think, that as you have not flown before, it may be better to book a fly/cruise. Yes, it will be a bit dearer, but, that way, the cruise line will do the donkey work of buying tickets, etc. You will also have transfers from the airport to the ship and back. You may be offered (at a cost of course), an excursion with airport drop-off on the last day, filling the time if flights are later in the day. Also, some cruise lines have reps. at the departure airport to help guide you through check-in etc.