My daughter's chose this cruise and it was all of our's first time. I live in Galveston, so it was very easy for me to get to the ship. We were a bit confused by the Sign & Sail set up before the cruise - what this means is when you get on board all passengers are given a card to use to purchase drinks at the bar, to get off / on the ship when at your destination etc. The card has a credit card tied to your account. You can use one card for everyone in your cabin or you can set up a credit card for yourself at one of the many kiosks on the ship. I feel this is not adequately explained on the Carnival website.
As to the ship itself, our balcony suite accommodated myself and my 3 adult daughters very well. There were 2 twin beds, the couch turned into a comfy bed and another bed pulled down with a ladder from above the couch. The amount of drawers and closet space was perfect for us. The bathroom had a shower / toilet and a bit of counter space by the sink it was a tight fit - expected considering we were on a ship!
We went to the Steakhouse that first evening - so delicious - strongly recommend the extra Steakhouse package. I tried the Serentiy whirlpool later that evening alone - big mistake. For some reason that night ...and just that night (I tried it later in the trip) the whole group in the whirlpool was trying to "hook up" trading room numbers and such. No my scene. But many others seemed to enjoy it.
I live in Galveston. There are so many great things to do here before you go. Awesome restaurants, Moody Gardens, The Pleasure Pier...I could go on and on.