I've been thinking about making an excuse like "after school on Wednesday I have to stay here to make up some work, and it's really boring alone, so maybe if you'd like to hang out with me for half an hour," or something like that. I'm working on it. But I plan on asking her tomorrow.
I don't really have to stay, but she doesn't need to know.
It'll give us ample time to get to know each other.
(I picked Wednesday because it's the only day I have open this week, and fancy that, it's Valentines day.
)