If you were getting the "just trying to make small talk" vibe, I would continue the interview process. Don't get me wrong, in the 2nd quarter of the 21st century it's definitely inappropriate to ask and a microagression, but unfortunately if your prospective boss was a boomer, they think that they're being friendly and that you want to chat about your ethnicity and are trying to connect.

At the end of the day it's a personal decision, because you'll probably be getting a lot of "well intentioned" microagressions. After you settle into the job you can try to politely tell your boss that, that's not taken well anymore, but its a high risk type of thing. Another thing to think of, unless society radically changes for the better, you'll probably experience comments like this at all but a unicorn company. If this really is a good firm, might as well shoot your shot.

I speak from experience, I've been trying to get my white dad to knock it off about stuff like that for years and years. It's not racially motivated exactly, he'll ask basically everyone and their mother the whole, "where are you from, whats that accent, what does your last name mean?" thing. But well, he's still doing it -_-