I would always recommend, to arrive at least one day before the cruise started.
Even when the flight is on time, your luggage maybe lost and you can get not until the next day.
In february, we lost all our 3 pieces of luggage, coming from germany. But in our hotel were at least 6 couples from the US missing their luggage and getting it in the night our some hours before the ship left the harbor.
So start your cruise relaxing with a pre-stay in an nice hotel, where you can meet the other members of your group.
By the way, it was Delta, who had many problems with the last transportation from our luggage from Chicago to Jacksonville. Thank god, we decided to go back from the overnight hotel to the airport to get the luggage. Otherwise we had missed the ship, because it takes hours to bring the luggage to your hotel.
Best regards, Marita