We returned from our Cruise a week ago and we were assigned late seating which was too late for our kids(5,3,1). They fell asleep at the table and I had my dinner delivered to my room on one occasion. Our Server arranged for us to get a table at the first seating on the last night, which worked out better for the kids.
You can board the ship early(we boarded at noon) and read the navigator to find out where you can request a seating change (Wavebands for us on the Wonder around 1pm). The Mickey Pool altered my plans and I arrived late securing the 20th spot on the waiting list.
Hope this helps.