Finished up my April/May Raja Ampat - Banda - Ambon charter which included 2 women divers ages 75 and 76. Both were traveling solo - 1 from USA, 1 from Canada. They are both brilliant divers, and have been out with my group trips several times before. The only concession to age is one of them has gone from a huge DLSR camera rig to a GoPro.. easier to pack and haul around the baggage!
I'm 63. Organizing trips, doing most every dive, and taking care of all the travel, running errands for divers in my groups, etc. I'm finding that the over 60 divers are doing more dives than the under 60's! I'm sure that's not true everywhere, but I seem to get a very experienced, well-traveled, fit, bunch of divers on my trips.