We are doing the Illuminations Cruise in October, another member of the DIS has booked this on our behalf, she booked on Sunday for October, I believe it was 90 days before, so you should be fine, just need to work out when your 90 day mark is.
She explained to me that she had to give her credit card number but this is just to hold the reservation, if none of us show up for the cruise, her card gets charged.. Hope this helps
I shared a wishes cruise with Jen_Uk last year - it was fab , I used my credit acrd to hold the cruise and we met up 48 hours in advance to just clarify that we were all still going ahead with it, at that point I could of cancelled and got a refund so even if its fully booked remember there MAY be cancellations nearer to the time. We then paid in full on the night