<human>: Can you condense the text into a few key points?

So me and this girl have been hanging out/ sporadically hooking up for the past couple months. It seemed like she was sending signals that she just wanted to be friends, but ultimately she came back and we started hanging out again. 

Recently, she has been dropping serious signals that she wanted me to ask her out (texting me late at night and early in the morning unprovoked, referencing us dating, etc.)
So finally yesterday I told her to come over because I wanted to talk to her. She immediately asked what it was (though I'm positive she knew what was up) and I kept telling her I just wanted to talk in person. Finally, I hinted at what I was going to say, and she responded that she wasn't ready to have that conversation. She just said that we would talk today and she needed time, but she has not contacted me.
<bot>: Why is a girl that was obviously wanting me ask her out acting so scared when I finally do it? Should I be worried? What should my course of action be going forward?