We are 61 and 58 and consider ourselves young at heart, except for some of the creaks!!! We sailed on Statedam in 2002 to Alaska and loved it. We are sailing to Alaska on back to back cruises from Vanc in July on HAL Volendam. As others stated, we liked the service and also the smaller ship size that still looks like a ship. We have now been on Amer Hawaii, Royal Caribbean, HAL, Celebrity, Carnival and Princess. HAL is one of our best. We have had a good time on each cruise and line. You make it what you want.
On HAL, you will be one of the younger couples but we found all ages on our last cruise. The shows and clubs will likely be less lively in the late evenings, which is fine with us, as I am up at first light and enjoy the solitude of the early mornings on ship.
If you give cruising a chance, I think it one of the best types of vacations to take. In fact, we have a hard time doing anything else!!!