corgi, my first wife's pop is a tough old WWII veteran... a Navy Seabee and was involved in the invasion of Tarawa.
He had one of his knees done about 15 years ago when he was about 70, IIRC. The nurses said they'd never seen anybody work so hard in post-op therapy.
If he can do it, you can, too. Grit your teeth and go hard.
BTW, I don't think anyone has mentioned this; part of your post-op therapy may include some work in the hospital bed with a machine that is strapped to your thigh and your lower leg and it moves/bends your new knee
for you from straight to bent in an increasingly severe angle to keep the range of motion there and prepare you for PT.
Yeah, it won't be fun either, but it won't kill ya.
Check this out: