Should I message her or wait until I see her in person again

I’ve been working at my university for the summer and I developed a crush on one of my coworkers. I want to hang out with her more to get to know her better and see if I would actually want to go out. Due to circumstances I don’t know when I’ll see her next (I do know she’ll be on campus like me). I don’t know if I should message her and ask her to hang out or if it would be better to that kind of thing on person, but like I said I don’t know when I’ll see her again.

This also isn’t a situation where we’ve never spoken, I’d say we know each other moderately well and have quite a few things in common.