My niece will turn 5 a week before our cruise. She is petite, somewhat shy in new situations and also best friends with my DD who will be 4 (2 months short of 5). We will be cruising together at Christmas so I imagine the ship will be pretty full. Do you think there is much of a chance of keeping my niece in the 3-4 year-old group with my DD or will she have to be in the 5-7 group? We are sure she will make out much better in the younger group.