So hard to generalise with our widely different personal circumstances (and I am ignoring money in this answer) I retired in Oct 19 just short of 54 and have no regrets.
It was a planned and positive choice. Once decided I relished my last year of work. I worked hard and long hours then stopped, personally I did not want to just taper out but that doesn’t work for everyone.
My wife, who is 7 years older, finished work at 55. I think it was good not to retire at the same time, she had fully adapted to her new life when I stopped. We don’t have kids.
I retired fulfilled and satisfied with my (demanding) career. I left while I still enjoyed it, and I think it is good to be able to say that. I did not want to work on becoming exhausted, frustrated and miserable; I have seen it with colleagues.
I had a few important plans already in place, and even with COVID some have worked out! Crucial to keep brain and body busy. You do need to work at it, but also learn it is OK not to be rushing around some times. I have never been bored, even in COVID times.
I am not a very social animal but if lots of your friends are in your workplace you do have to make an effort to keep in touch, however I think the important workplace friendships endure even when you stop working together. I have also spent time with other friends that I was just too busy to see that much before. I do get more quality time with my best friend too, who I married.
I think this thread will show it is not for everyone. In my job I met plenty of much older people who were entirely content working to a very good age, and others who really struggled mentally after retiring young. My father basically became an old man the day he stopped working and my brother was bored within weeks after retiring at 58. For both of them retirement was loss of status, identity and purpose.
So my advice; only you can decide if it is time for you and your family. Plan it, and don’t start looking for stuff to do only after you have stopped. Some structure is good and it does take a while to adjust. Think of retirement as a beginning not an end. One of my volunteer ‘jobs’ is responsible and challenging and I hope will give me satisfaction for many years. I could not have done it when working.
You don’t live for ever. My wife had a serious health issue twice in her fifties and if it comes back again things may not go well. We are lucky enough to be able to have retired now and we both savour that opportunity.
I have no idea if this waffle helps you, or anyone else!