I think your SM is technically within policy to allow you to work (even if the policy is pretty messed up regarding this and a lot of COVID stuff). Its totally up to you at this point but I’d personally call out because I am terribly afraid of putting my coworkers at risk, and obviously having callouts sucks when you’re working but I think your coworkers would rather that than get COVID, you know? I’ve been told that starbucks won’t fire you out of retaliation (trying to remember the correct term they’ve used) but I’ve heard of people being fired for small things as excuses. Depends on your SM and how badly your store needs you tbh so I wouldn’t tell you that definitely you wouldn’t be fired for calling out, though it’s unlikely.

According to $1 Pre-Check Guide, Starbucks is only requiring you to isolate if you have unexplained symptoms, if you’ve had ongoing close contact with someone who has tested positive, or if instructed to by a health authority.

They’re not presuming positive cases, so until your girlfriend tests positive, her potentially being exposed is not enough for you to be required to stay home.