How to tell if a girl is struggling with her sexuality?

I have this friend I have been badly in love with for two years
I think she is gay but if she was she would have to be deeply in denial and scared of ever coming out
I feel as though she used to flirt with me a lot, she would grab my thigh and hold it or my hand or touch me but always made it out to be a joke
Would always bring up lesbiany things e.g my folder at school is purple and she went oh purple and green the lesbian colours
I feel maybe I pushed her away or scared her I was confused whether she really liked me so I would sleep with a lot of guys and talk about it infront of her
Now she has a boyfriend who she really doesn't seem interested in at all
And I started acting upon liking her very slyly like in class we were passing notes and I wrote that I really liked her but with our humour we have we laughed about it and made it a joke and she replied asking to take me to prom (once again a joke/sarcastically)
Now she's sort of backed off
What are your experiences with girls in denial? Or girls having a hard time accepting themselves in high school? What should I do?
She's hardly every serious has a class clown like personality always being a fool
That's why I can't tell whether she's really joking with me or joking but trying to send hints