I was told when younger about you only regret the things in life that you didn't do, not what you did. And I took that to heart. Whatever I wanted to do or try, I did 100%
I never had a midlife crisis but I had something similar when I turned 60 (like,, "holy shit, am I really??")
I looked back at my life wondering if I felt that it went OK and I was able to see it all in perspective and YES my life has far exceeded my expectations for myself. Basically because I didn't have any.
So now at 65 I can look back with that satisfaction and joy but life is rougher now. In terms of loneliness and having to say goodbye to my only close people that I love. So that's kinda sad. Now I see why people have kids (I didn't)
But I just got a puppy?