Need help deciding what to do next (sexuality question)?

Hi there :) First of all, this isn't one of those, "I kissed a girl, am I gay?" questions. There's more to it.

The story: One of my friends (Selene), had a party at her house at the beginning of the school year. We only started to become close friends a few months prior to it. Lots of people were drinking and Selene & I had a little bit. Where I am, we are all of legal age, by the way(: Then we decided to play strip spin the bottle. Pretty quickly, most of us were either in bra & underwear/boxers or close to it. Selene was in her bra and underwear, and I was in my bra with shorts. We changed the change to dare spin the bottle. People did their dares, blah blah blah, and then it was her dare. It was to make out with me for 30 seconds, in front of everyone. By this time we were both sober because we only drank a tiny bit. Nonetheless, we did our dare. At first I was laughing because I was super nervous, but then got into the kiss. It was a fun experience. (She was the first girl that I kissed more than just a peck). That's about it at the party.

Nothing really happened between us other than being friend for about a month or so, until about a few weeks ago. She would sometimes sit on my lap, or subtly touch, hug, or just have her arm around me (non-sexually) in the hallways. Last Saturday night, we hung out, just the two of us. We asked each other ridiculous, sexual, and embarrassing questions just for fun. At lot of our questions included how we feel about each other. We were smoking, and did a shotgun smoke. That meant nothing to either of us, because our lips barely touched. Then when she had to go home, I kept pulling her to stay and we had our arms wrapped around each other’s waists. Then I leaned in for a kiss, and right before our lips touched, I pulled back and said that she should go home because we were both already late.

Yesterday at school, when I saw her on the stairs, I got really nervous and awkward to talk to her, probably because of what happened on Saturday. After school, while we were walking I noticed she would touch my hand or hug me, etc.

Selene has a boyfriend, but she is bisexual. She's actually had a girlfriend before too. I'm straight and always have been. But this girl makes me feel super confused. Sometimes I think I like her more than a friend, but maybe it's because I know that she is bisexual, so I'm fooling myself into thinking I like her.

Should I confront her, leave it alone, or what? What do you all think?