Almost to my 1 year anniversary of my replacement (age 65). Hardest thing I could imagine to come through, and I thought I was well-prepared and healthy.
You didn't mention if you had help/spouse at home. It is imperative that you have someone around when you go home. An ice-machine is necessary for pain control and swelling as well.
It is grueling and a huge decision. As the other supporter wrote, everyone is different, so age is not the only thing to consider.
Best wishes.