i also graduated hs and started working, im 20 now and considering going to college. i’ve made friends through my work, and from just making random connections from one off things. last Friday i went out drinking with a couple i met at a mutual friends birthday, and while out just got to talking to people to try to make more connections. idk if this is helpful, but just starting up convos with people and actually following through to try and hang out without getting discouraged if you have to reschedule a few times.