Why is this so confusing?

there's this girl I like (I'm a girl too) and today I met her at the mall she was with her older sister, me with my younger cousin. And she would put her hand on my butt and like in my back pocket. Not that I didn't mind. The thing is we always flirt and stuff whenever it's just the two of us so I kinda didn't know how too act. But, there was a story behind why she put my hand on my butt so I guess that's why she done it. She would get close too me and talk too me. Although, some was about her new boyfriend which I wasn't too happy with. Also, I think her dad doesn't like me maybe it's because he thinks I'm B.I (which I am but still in the closet). I just don't know why this is so confusing.

When two people start doing physical things with each other before there is any understanding or boundaries between them, it always produces confusion. Add a third party (the boyfriend) to the equation and it becomes very confusing.

Think about it. If all three of you clearly understood the part each of you play in the triangle, there would be no confusion. You are like actors in a play where neither of you understand the part you're playing.