How do i know if a girl likes me?

ok so at the start of November i started to talk to this girl.. ( ok so one day i just happened to post a little ad on craigslist. yes i know not the smartest thing to do..) but anyways she text me first and for the first week we where text in like crazy . then almost 3 weeks later we finally met. and we had a blast, so that week we hung out at a club then she spent the night. and almost every time we chill now she ends up staying the night . i asked her out and she said that shes likes what we already have and that she told her self that she doesn't want to let go of me for a long time. witch is it ok? she really enjoys hanging with me because shes always like oh this night is going so slow when she is at work and later that night we'll be hanging. so here is my question now we hardly text all the time or i have to txt her. Is she playing hard to get or what ? or am i just bugging out ? I really do like this girl!! and the 15th of January she is my date to my fireman's formal dinner..