Sorry I didn't get back to you sooner, and that nobody else picked up on this. REST COMFORTABLY!!
As long as the cruise line booked your flight, you're probably one of several coming in on the same flight. The ship will be held for you. There is no need to worry. The same holds true with shore excursions. If you book with the cruise line and an excursion is delayed, the ship is held until you get back. We've seen the opposite happen on a few occasions, people going on their own to save money. My answer to this is you'll have a beautiful picture of the ship taking off. On a recent trip to Northern Europe, 3 young men missed the ship in Oslo. The Norwegian Coast Guard rushed them out to the ship, and the ship dropped rope ladders for them. OK if you're young, but not at 60. Have fun, and don't worry about missing the cruise.