Have all your ducks in a row(pick out a flight you'll go book if needed, find a hotel, make sure your passport is valid for 6 months form sail date, personal schedules etc) before you book because it's non-refundable from the second you make the one and only payment. If you don't care about scheduling Palo, Princess meet and Greets or any specific Port Adventures, then no there are no other issues I can think of. A last minute cruise can be so much fun, none of the pressure of waiting 18 months from opening day booking. Just a few short weeks and your on your way!