Well, 5 is possible and is done quite often but it will be tight and I personally would not do it, especailly with three girls! CCL has larger standard cabins than other ships but there will be no room with the four beds and the rollaway in the middle not to mention the bathroom.
As far as what cabin you will get? You booked a cat4A Gty and you have to figure that you will get the worse cat4 cabin on the ship. Anything above that is a bonus. You will probably still be in an inside cabin even with an upgrade.