Love responses, and may request permission from Lou to re-use them in a different format.
In all seriousness, I feel I am one now, but have just recently realized it. Its sort of a long process, accelerated the last few years as I notice my former 255 yard tee shots have dwindled to 225 or less. Muscle mass slowly declines with age, but it takes the brain a while to figure it out.
In some ways, it starts earlier. Got to play Pinehurst 2 with Rees after his renovation, and he insisted we all play 6100 yard tees so we could enjoy ourselves. I did, and then it took me about ten years to realize moving up a tee did make golf fun (hitting mid irons to greens instead of hybrids, etc.) I started by moving up a tee to accommodate other seniors, D players, grandkids, etc. For a while, didn't want to admit I just liked playing shorter and shorter courses. Maybe the final "straw" as it were, was choosing 5700 yards over 6100 yards one day. Yes, it was cold, ball doesn't travel as far, but I soon realized I was getting pretty good at finding reasons to play at about 6000 yards or even less, the hallmark of senior golfdom, no?