Let me preface this with the 60-40 rule. This rule is something people in this community always always forgets. There are so many butt hurt guys here wondering what they could've said or done differently to secure the hookup but sometimes (40% of the time), there are things outside of our control that will cause women to not be interested or not willing to fuck us at that moment. In fact, even MPUAs face this from time to time so it might not necessarily be your fault!
That being said, the other 60% of the time lays on us. Based on your conversation, you said you got some laughs out of her and got basic emotional investment from her. This is fantastic; however, what I'm not hearing is:
Kino escalation
Sexualizing the conversation
Cognitive Dissonance (when she was on the fence)
How you stated your intentions early and clearly to her
All of these things are important to seducing her and building attraction. Based on your description, it seems like all you did was build comfort. In other words, all you did the entire night was establishing yourself as a friend, which possibly explains the drop in text responsiveness. She showed IOIs before and was attracted to you but due to your lack of game (60%) or some other reason (40%), she stopped being attracted to you.
Summary
Learn from your mistakes
Be grateful she rejected you. Your time is important and you don't need to waste any more of it on her