We went for the first time in October and my two oldest (then 7 and 5 1/2) loved it! The CM that took my reservation did say it filled up fast, but call anyway. You never know until you try.
As far as a deposit, to the best of my recollection, they did take a credit card number, but didn't charge me until after the cruise.
Hope you get this, my kids are already asking to go back when we go again in Oct. 2005.
Lori P.