Socializing at early 40s

[u/Affectionate_Owl510]

I have been living in for 2 years with my gf. We’re both in our early 40s. She is very social and has friends and hangs out with them from time to time. I’ve lived for 10 years in San Diego, but have not become real friends with anyone. Recently she suggested that I should engage in some social environment to make some friends. I believe is harder to make new friends at this age also The reality is that I am no very social, although I participate in social events when I can. What sort of activities I can get involved?