College Crush..

Hello, My name is Clay I am 21 years old I am a college student, and I happen to have a crush on a girl that is in one of my classes.
Ever since the first day of class she has been staring at me and tried to converse with me but she was a bit shy. The following week I saw her in the art studio and we were both by our selves drawing, and she kinda gave me a good vibe, I noticed that she has not done this to any other guy in class.

Little by little we began talking, I did notice that I was nervous a bit, and I also noticed that she was as well when she almost dropped things to the floor. Anyways to make a long story short... She is dating some dude from her hometown and it is a long distance relationship since they don't have time to see each other and it is a 2hrs drive.

I have a feeling that she likes me though, I invited her out to dinner and a movie and when she wanted to pay for everything I payed. The next day I bumped into her in the street and she invited me to her apartment to watch a movie, she also introduced me to her brother (which I think is a good thing).

I also notice that she is always around me in class and by her body language it looks as if she is flirting with me without saying a word by fixing her hair every time I look at her. I also noticed that she has a straight eye contact with me all the time. She invited me to go with her and her brother to a festival this Saturday coming up, but I also invited her to my dorm for Friday night so we could watch a movie together.

How can I flirt with her without getting her uncomfortable? I really like this girl, and I want to see if we could go to the next level. I'm actually taking my time and not trying to rush.

P.s. me and her had a conversation about long distance relationship, and she has told me that since they far apart from each other they both know what could end up happening. I also don't have enough experience with girls and so I don't want to mess this up she is a nice girl, and stands out from the other girls in my school.

Well, you already took her out on what was clearly "A Date". Unless she's sort of clueless, she knows that you paying for dinner and a movie is more than a friendly get-together. But she has a boyfriend and is still dating around, so that would be a red flag for me. Do you think that if it ever got serious that you might be a little distrustful of her around other guys, since that's how you two hooked up?