I would not say that I wished that I had known it but when I went through my 50s I saw a lot more people than I would have expected either die or develop major health problems. There was one year in my 50's when I went to three funerals for people that were roughly my age. None of the people were real close to me but it does get you thinking. A lot of people that are that age, or their spouse, will also have a health scare that they get through OK but it will cause them to reprioritize their life.
I worked in a mid size Megacorp IT department that had about 100 people. The company has gone through multiple mergers but it has been around in various forms for over 50 years. I retired a few years ago just before I turned 59 and the amazing thing is that I was the first person to voluntarily retire out of that IT department. Some people decided to retire after getting laid off and getting a severance package but I was the first one to pull the plug myself.
I suspect that at that company a lot of age bias was with more with the hiring and it was rare that anyone much older than 40 was hired.
This means to retire at 60 you would probably need to work at the company 20+ years and few people will work at one company that long even if they are not laid off.