IMO, its best to make romantic intentions clear pretty quickly (like within the first 4 hours), touch her alot (not grope, like touch you on the shoulder while you're talking), hold good eye contact, etc. If she doesn't take to it well she doesn't like you, if she does she probably would at least consider you. Once you lose the momentum its almost always too late (if you like a girl don't try to hide it, girls want sexual affections as well but they're less willing to take risk because there's more social stigma against them being forward about wanting a boyfriend/sex/etc & if you're pretending you only want to be friends/keep it platonic she will probably lose interest).
Life is short so best to seize the moments. Get accepted or rejected quickly & then you won't be left wondering. You can move on to the next candidate.
When you live in your head wondering you won't learn much. When you put yourself out there over & over you can at least analyze where you went wrong (or perhaps you're learn what type of girls are worth pursuing).
Once you're putting more energy in than the girl & the ratio is getting worse & worse its probably too late to salvage anything (this is from personal experience). So in answer to your question - Move On! You're in University, there are lots of new opportunities to meet women.