maybe both? she graduated from stanford this past spring and finally settled back in san francisco at the beginning of summer. she's been working in the same bar for a couple years now, just over the summers and now she's full-time. maybe they met a couple years ago at the bar and maintained their friendship, so after she graduated they became roomies? it could be a situation where his roommate moved out leaving a spot open and it was super convenient for her to take it since she needed a place anyway.