I was on the Celebration on the Ta in November. I had an inside and was on deck 5, which was originally a semi handicapped cabin. I did not request nor want such a cabin, the bathroom had accommodations but the cabin was no bigger than any other normal/small inside. I was able to move to a cabin a few doors down to a standard cabin which was the same size. I must admit I had to get into the bed which was 2 beds put together from the front, since thee was not enough space to walk along the side of the bed. In getting to know others I saw some other cabins. I saw one that was 50 -100% larger than mine with a couch that was also an inside. I saw another inside cabin that was more square than rectangle and that also seemed more spacious. Just wanted to give a heads up that there are a few different types of inside cabins, as well as location being a consideration. I was very happy on deck 5, and a very short walk from the elevator.
I loved the Celebration, enjoy your cruise.