Don't know if this will help....I genuinely hope that I'm offering a positive thought here....
So, I am very lucky in that I have a good group of close friends, and a few very old friends who live away.
I work part time and study, so I often struggle to see my best friends who live just up the road.
I often meet new people, at dinner, or classes, and I do really like them. I can see that we would be friends, we have stuff in common, same sense of humour etc. But, I wouldn't make the effort to get better acquainted, simply because I don't have the time to see my friends I already have, and so any spare time it would be the priority to see my existing friends, and not to nurture new friendships, much as I would love to.
So, those people will remain to be 'the lovely girl at Pilates who I have a laugh with at the back' but that's where it stays.

I'm posting this because I really agree with Growly above, and my experience is that it must be very hard to make new friends after a certain age, and often that's simply because people have work, family, household, existing friends, and no time! Not because there's anything 'wrong' with the new person.
Hope that makes sense. Sorry for the waffle.
Btw I made friends for life when I went back to studying!