Backstory: Shes relatively cold and reserved, quite hard to get and highly inteligent. Never had a bf.

I've recently been going out with this girl, our usual dates were mostly getting to know eachother. We had parts in our text conversation where I asked her how she defines our nights out, she asked me to define them to which I replied that she has my curiosity and we shall see about my interest. She responded that she feels the same way.

Fast forward to yesterday, an date which she called me on. We went to a caffe and I kept on escalating the whole interaction. I showed her a couple of cool places and jokingly asked her what type of night out this is, to which she smilingy replied that its a date. I teased her a bit about it a bit. Later I hugged her to which she replied by laying on my shoulder and almost falling asleep for 20 min. After that we went away and when my bus came, i kissed her on the cheek and went my way (her best friends and basically our whole social circle considers me a fuckboy so I've made an effort to go slow with her).

Now about the issue. She usually messages me after we are out and multiple texts a ton. If she responds short she will always double text and make an effort to keep up conversation. After the date, I decided to message her as I concluded that she would have thoughts if she acted right and shit. I asked her if she arrived home to which she responded with an "I did". I responded "good" and that was the end of the conversation. My questions is, why is she suddenly so cold after a date on which we did much more than any of the previous ones. I'd be thankful if any of you more experianced guys would give me insight on this. Thanks.

Edit: Shit, this was eye opening. Getting clouded by illusions and emotions and not setting frame got the best of me. Thanks you for the feedback.