I'm new as well. I started at 41 and have only been playing maybe 8 months.

Although I do not have your years I did discover a physical issue due to my age and physical condition.

I deleloped a severe pain in my left thumb (fretting hand) due to my tendency to play without a strap. Trying to navigate to fretboard and support the weight of the guitar caused my thumb to drag sideways. This resulted in tendonities. It took 2 months of rehabilitation and rest to recover.

I recommend always using a strap even when sitting so your frethand can move more freely.

My fingers developed calluses in a few weeks of playing 2 to 3 hours a day.

Hope this info helps and good luck with your new life as a guitarist :-)