Regarding the age (mine) I am 67, so I think it's getting a bit late even now to consider a puppy - adding a possible 15 years on would make me 82...I am 71 and have to admit that I won't be getting any more puppies as if they live for at least 12 years then I will be 83 and who knows if I could have health issues by then.
If I outlive my 3 dogs that I have at the moment then I would probably consider taking on very elderly rescues, the age that most people would not even consider taking on. This way they can be loved and cared for, for whatever time they have left and we can both have company in our twilight years.
It is very sad the amount of elderly dogs spending their last months or years in a kennels when their owners have just handed them over in order to get a younger dog without a thought of the distress and confusion of a loving family dog that has spent all it's life with one family only to be dumped for a younger model when it gets too old to run around and 'be fun'