All my life I've thought I was an introvert. At school I was quiet to the point loneliness. As I got older I developed a quiet confidence in my ability to achieve most things, as long as it didn't involve being sociable. I married a good kind man and for 30 years he supported everything I wanted to do (including lots of study and career progression) but also enabled me to avoid anything sociable by basically doing all the talking for me. At work I was brilliant (IMHO 😆) at the technical aspects but was held back by my inability to do anything that looked remotely like networking.
Then DH died and I was on my own. Somehow, I have become a social butterfly and built a life that revolves around being out and about, I've joined groups, been on holiday, even shared a room with people I don't know very well. I can turn up to events and chat to anyone. I've got a new job and have thrown myself into every social/networking event that comes up.
I still enjoy my own company and do that better than I used to as well - love going to the theatre and dinner on my own, which is something I'd never have done "before".
I'm enjoying myself but even to me it seems odd to have such a personality change in your 50s.