You are allowed to make new friends, even as an adult. As someone who has lived in a dozen cities in my adult life, it does take effort. But it seems like, as the author is willing to take the effort to track and adjust their life, they are likely willing to put in time to make new friends.
I've found meetup.com to be an excellent way to make friends, as well as hobbies. (for me, standup comedy and DJing were excellent).
Repeated interaction is a necessary first step to friendship, you cannot befriend someone you don’t see. My gym buddies are now my friends, and we see each other regularly outside of the gym context.
Also, most of my friends don’t know when my birthday is, so that’s a bad metric imho. Birthdays are not universally important across the population.
lol wut. I have friends now of several decades who I see regularly (make effort to visit cross country) none of whose birthdays I know or who know mine.
Re: DJing- I recently got into this. Do you DJ private/house parties or at nightclubs? From the forums I’ve read, people say it takes a lot of networking to get a gig/slot at a nightclub. I guess you make friends along the way too?
I've found meetup.com to be an excellent way to make friends, as well as hobbies. (for me, standup comedy and DJing were excellent).