I reckon I qualify as an older pilot and age has affected me. I have no wish to die, nor am I afraid of dieing, I just hope it is not painfull.
I find it easier to cancel a flight or to turn back, but the greatest effect old age has on me is that it reduces my confidence.
There are things that I know I can do quite safely, but I bother about them until I actually get into doing them. Flying is one of those things, but sometimes I just have that feeling that it is a bit beyond me. A long distance flight can be viewed with trepidation, until I say to myself, just start it and if I still feel uncomfortable, then turn back. I haven't turned back yet and usually have a very enjoyable trip.
Just thinking back, I have turned back, due to weather and I feel I made the correct decision.
Someone mentioned the red DH. That was one of my turn back days. I was at Monto ready to leave because I didn't like the forecast weather when he arrived. I as safely hoe when he crashed due to flying into cloud.