Here is a recommendation for you. I have not invented it, but I have seen people try to use it on me, and I think those people have a point.

Give your email or IM address to her. Give her a way to communicate with you off the Ok Cupid site.

I do not know if a girl your age would react the way I do because I am older, but to me, a person's willingness to become less anonymous (even if it is not an email address with a full last name) shows more interest, more confidence, and more seriousness.

I might be wrong, but at least it won't hurt. Just not on this girl - I am suggesting it as something you can try on new girls you contact.