Hi Pomelokiss, I'm so excited for you. Princess is our favorite cruise line and I'm glad to be going in December. We used to do traditional dining, but now we do the Anytime Dining. It works much like a restaurant. If there is a wait, they will give you pagers. Then you can go and do whatever you like until your pager goes off. They will ask you if you want to share a table or not. We normally share so we can meet fellow passengers, however, you are not required to share. It is only an option. You will be served the same food as those in traditional dining.
We do eat our breakfast and lunch in the buffet since it works out better for excursions. They have one of the dining rooms open for sit down service for breakfast and lunch if you prefer. You also have the option of room service.
I totally agree with Nadine, come in a day before the cruise. It alleviates so much stress and allows time for the "just in cases". Even when we drive to our departure port, we arrive a day before sailing.
I know you will have a marvelous time. Please come back and let us know how it went!