How to get her to be my girlfriend?

okay so me and this girl have been seeing eachother for about a month now. I've been spending the night with her, and she introduces me to her family members and we've had twice. lol I was a virgin before that too.. I know she really likes me because she comes and picks me up ad hangs out with me every day she has off. I just want to be able to hint subtly that I want to be her girlfriend not someone who she just hooks up with.