How about missing incredibly easy, short shots that you would never think you could possibly ever miss in a lifetime, or screwing up an incredibly no brainer easy positioning, which leads to a harder shot, which you then of course miss.
Also, how about double hitting the cue ball, and I’m not talking about a situation where the cue ball is close to the object ball or accidentally touching the cue ball with your tip just before starting your final stroke. I’m talking about literally double hitting the cue ball on your stroke through the ball - the equivalent of the yips in golf. Doesn’t happen often but when it does, it’s frightful, and usually you are the only one that knows you’ve committed the foul.
After playing pool for most of 50 years, in my experience, none of what you are describing sounds like the effects of aging to me.
Pool is a brain game and once you have learned good technique execution errors typically result due to lack of focus and lack of focus tends to result in rushing the shot. The shot consists of choosing the next 3 shots, deciding where the cue ball needs to land to keep the pattern going and how much force/spin (if any) is required to stick the landing, clearing your mind, executing your standard pre-shot routine, addressing the shot, warm up stroke(s), and pocketing the ball. If you rush or omit any part of that, or are trying to balance the checkbook during the process your results will suffer.
What typically makes it worse is a player's reaction to execution failures. Getting upset or doing anything other than replaying the shot to figure out what you did wrong (was I distracted/unfocused, did I move my shoulder? etc) is a wasted opportunity to improve. If you don't know what caused the failure, how are you going to fix it?
When players don't know what is causing their problems they can start questioning their abilities and can quickly auger in, as the pilots say. i went through this sort of slump due to onset of double vision coupled with life threatening levels of stress due to the very good paying job from hell and trying to take care of elderly parents. Not having time to think much about anything not related to the above, my game went in the toilet and I ended up quitting in frustration.
After two eye surgeries I tried league again and was still struggling until I was able to retire and leave the job behind, the parents passed and was able to wrap up their affairs. It took some self analysis to figure out focus was my problem and more time to calm the hell down. After having the time to exercise get back into yoga, and practicing focusing, I am happy to say that I am back to kicking ass in both leagues that I play in.
However, it is a process that requires rinsing and repeating. With the exception of the elder statesman on our team (he is 77 and the local custom cue maker) I am just about the oldest player in the local leagues (will be 68 next month) but am now shooting very close to what I was at 20. I am coaching my younger league team mates (the ones that will listen) and it has helped their playing.
Back to your stoking issues, they can be caused by lack of focus, anxiety and/or you have developed some bad habits. From personal experience, anxiety can make you flinch, twitch, stab, lurch, punch or otherwise goof up your stroke. I went from having a worry free instinctive stroke when I was 20, to losing all confidence a few years ago. I got my stroke back by independently coming up with and using a variation on a drill described in this thread:
https://forums.azbilliards.com/showthread.php?t=503614
But the thing that made the biggest difference in my overall playing was practicing focus, which also has a calming effect and puts me in that confidently hyper aware state I seem to need in order to be a dominant pool player.