My husband and I took the very same cruise as our first cruise - about 2 years ago. As far as new-ness of the boat, I have nothing to compare to. I will say that the experience was so good that we're cruising again this February - but this time trying Celebrity Horizon for the Western Carib. itinerary. I can say that the multi-story main lobby with glass elevator is an impressive sight when you first board the ship.
-Nassau: Beware of TONS of people at the port trying to sell their wares, braid your hair, give horse-and-buggy rides, etc. These people are relentless. Just ignore them. We took a short cab ride to Paradise Island to check out Atlantis resort, which is just awesome. There's a beautiful casino and a really nice aquarium (cost=$25 if I'm remembering right). Also beware - eating at restaurants in the Bahamas is VERY expensive. We went to a diner-type place on Paradise Island and paid $35 for two cheeseburgers.
Cocao Cay - AWESOME. I wanted to stay behind and live there. You can snorkel (when you rent the equipment they give a little how-to course - it was my first time snorkeling and it was easy and fun!), float on comfy mats you can rent, drink some tropical cocktails (guys walk around selling these) and you get a free barbecue that was yummy. Catch an early tender out there - it is worth staying on the island for as long as you possibly can!
The ship: The food was good in the dining room, just average at the buffets. The shows were a lot of fun. An inside cabin is quite small - I highly recommend spending a bit more for a cabin with a window and/or a bigger cabin. The pools are salt-water.
One other tip - don't miss the show on the last night of the cruise. It's some kind of contest with audience participation that was supposedly an absolute scream. We missed it because we were packing our stuff to put it outside our rooms before midnight (this is the protocol on the last night). So remember to pack your bags before dinner and don't miss that show!
It's a great first-time cruise. Short but sweet! Enjoy.