It's her right to not disclose the information, but I'd be bothered if my T didn't tell me and got hostile over the question. Yes, it's a personal information, but so far everyone I've met talks about it. People in a store I often go to "oh, are you vaccinated yet?", I have asked my dentist whether he's vaccinated... my T disclosed getting the vaccine without me even asking.

Anyways, I'd wear a mask regardless of what her answer was. Vaccinated people still can spread the infection if they get it, so better safe than sorry. And since you'll switch in a few weeks anyways, I'd probably not dive into the topic more. If this was a permanent T, I'd honestly probably stop seeing them, not due to not being vaccinated but due to not disclosing it.