This is why you should never book directly with the cruise line. If you used an agent, they would have spent time with you going over all the details. Plus, if you book with the cruise line and have any problems, who do you think they represent?
With that said, as you've already been advised, NCL is noted for their anytime dining approach. (Of course, now all cruise lines offer this as well). When you go to the main dining room, it's like going to a restaurant. Depending on when you go, the type of table you'd like, and whether you want to be seated with others or not, you may be seated right away or you may have to wait a while.
However, and obviously this is just my opinion, the food in the main dining room is just okay - nothing special. So as I tell everyone booking an NCL cruise, plan to spend an extra $100 per person while on the ship to try the specialty restaurants because their food is much better.
Enjoy your cruise and let us know how you like the Getaway when you get back.