On the other hand, she could be waiting for you to make the first move. Which is why I suggested a casual outing, rather than an actual date. You just need to catch her alone for a second and say something like "I'm going [insert event here] on Saturday, do you want to join me?"
If she seems interested, but can't make the specific date, ask her to suggest a more suitable one. If she says a flat-out no, it's a good sign she's not interested but nobody feels embarrassed about it.
It's been just over a decade since I was at school, but I can tell you that if I told a boy he was cute it means I fancied him. If I told him he was nice, that would be a polite "no, I'm not interested". Obviously she might not say things the same way, but I'm just giving you my opinion being an actual girl.
