This girl is confusing me, what does she want?

Before I get started, I'm gonna give a little bit of info. I'm 22 and she's 19. We both go to college together for Film and TV productions and have had classes since last term and this term together. We were partners in our last semester and we're partners this semester. We'll call her Kelsi

Last term we had to do location scouting for her short film. We walked to a place and she was texting on her phone. After we got there and was walking back, she tripped and I caught her and asked her if she was okay. Then all of a sudden, her ex just pops up out of nowhere from a classroom. Those two go off and talk for 5 minutes. They hug and she walks back. She tells me that her ex wanted her to go with him but she said no because she was walking with me and that she wouldn't leave me cause we're friends. Then one of our classmates asked me if we were dating cause he liked her.

(Look at the updates cause there's a few more paragraphs)

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This term we get in the same class and now things are really weird. She tells me that her ex thought me and her were a thing and hated me because of it. When we're standing up in class while our instructor shows us stuff, she'll stand near me or try to stand directly infront of me. If the instructor says to grab equipment, she'll follow me. She'll ask me to stay after class to help her with stuff. If I'm standing and there's an open seat next to her, she tells me to sit next to her.
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She'll playfully hit my arm or try to touch me. She'll tell me to text her. Okay cool. So she likes me. That's what it seems like right? Well read the next paragraph.

So I'll text her, no response. I'll call her no response. This is a normal thing. Where she'll act very flirty in class or in person but will not respond to me in text. I'm an introvert and also take ADHD medicine so in class, I'm not talking and basically just silent.
This girl is confusing me, what does she want?
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