Great news!
When I had my "brain surgery" (don't laugh, and no derogatory comments, pls), the docs were absolutely amazed that I walked two miles the morning after the surgery, and I was only one of two persons in their experience with that procedure to get out of the hospital the very next day. I was about 62-63.
Lately, my wife's knee is so bad that she can only walk for short distances without an expensive brace. But she can bicycle 15-20 miles.
But, do take it easy.