If you have about 40 cruises under your belt already, the following is probably old news to you, but here goes anyway:
Regardless of when your cabin is available to enter, that doesn't mean that your luggage will be there then. I've seen it come as late as 8:00 PM. I wouldn't worry about it though, it happens very rarely. Just enjoy the cruise.
Short experience we had, ONCE: On one of our Star Class Sailings, as usual, a crew member met us at the entrance of the terminal (Port Everglades) and took our baggage directly through security to our suite, it's supposed to be in your suite before you get there. One bag didn't make it to our suite until the next morning. It must have fallen off of the cart and the crew member didn't notice it. Our Genie actually did the search and found it in the bowels of the ship somewhere. I didn't lose a second of sleep over it. I knew/had faith that it would be found, it was. Fortunately, it only had our sandals, sneakers, and swimming attire in it anyway.