I accidentally texted a coworker (who I have never hung out with socially) who has the same name as one of my friends if she wanted to go to a music festival with me (like 5 days close quarters camping) and she said yes without hesitation. I met another girl at a party -- I knew of her because she was a friend's friend's ex but never actually talked to her. I just declared that we were best friends, we got drunk, and skipped out at the party to hang out/meet her other friends. She's my maid of honor. Met a guy during a charity scavenger hunt where the theme was to do mildly embarrassing things in public we hit it off after I had him take a picture of me licking a bronze statue's butt. I'm now in his softball league. I met a woman on a cruise after rescuing her son from the on-deck ropes course when a huge storm hit, we live super far away but play animal crossing together.
I went from "oh no without school it's gonna be impossible to make friends" to "no actually this is a million times easier." All the stuff that makes you uncool as a teenager makes you interesting as an adult.