because my surgeon tried to put me off with various things like my age (63)
I was 35 and was being told to wait till I'm 60. I couldn't take care of things around the house. I couldn't sleep. I was in so much pain. Had to travel 6 hours to find a doctor who would do the surgery. First one at 36, second 3 months later at 37.
My mom said her aunt went through similar, but didn't have options. Because of her pain, she couldn't be active and her health deteriorated. By the time she was "old enough" she wasn't healthy enough for surgery.
The surgeon who did my surgery said they typically still wait till people are older. Not because the implants won't last, which is what the reason used to be. He said younger patients more frequently say it feels unnatural and then become less active. That's part of the reason I had a partial instead of total. Each knee has it's own quirk, but I can do stuff again!