My grandmother had knee replacement surgery several years ago now. She was about ten years younger then you when she decided it was the right option for her. The anesthesia did not have a terrible effect on her then- but since she has had other health issues and multiple surgeries. With each event and surgery the recovery has been a bit more complicated. She is now 78 and her advancing age, other health issues, and having multiple procedures in one year have become a lot for her to overcome. However, the future is never certain and the knee replacement did benefit her for a period of years.
The most important thing in my personal opinion is to decide based on what is best for you. It will be painful and a lot of hard work with no real guarantees- as with anything in life. Just remember an elective procedure is just that- a choice. Pray about it, get informed, and rally your support system. If you decide it’s what’s best for you be proactive and engage your care team early. You are already way ahead of the game. Good luck on your path to better health! You are in the driver seat on this one!