Knowing absolutely nothing about her gaming preferences/abilities? I'd say Untitled Goose Game. It's short, it's not terribly difficult, it's silly, and the co-op mostly just amounts to dicking around. It's a solid casual experience that would let us share a few laughs and figure out what to play/do next. We'll put aside for a moment the practical consideration of bringing a digital game (though, being digital, if I'm bringing my whole Switch along to play it, that opens up every other digital game I've got on there as a follow-up).
In practice, though, if I'm providing the game for a game date, the game date is probably at my place and I don't need to "bring" one. If it's at her place, I'd expect her to be providing the game. Either way, I'd expect that we'd have discussed gaming preferences beforehand and arrived at a decision on what to play, so I wouldn't really be making this decision on my own.
Edit to account for the update: I'd still say UGG. Assuming she hasn't played it, it's a fun one to watch people react to.
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