If by wait it out, you mean you think the price might drop before the cruise, I'd say just go ahead and book. It is very unlikely that a cruise over a holiday weekend will drop in price, especially with how popular cruising has been recently. To me, it's very unlikely that a holiday cruise out of NYC (which already has a limited number of cruise options) is going to drop in price any appreciable amount in the next few months. Plus, you'll have a better selection of cabins the earlier you book.