Bisexual first relationship with girl!

I attended college for 2 years at one school then transferred to another school 8 hours away. I met a girl, we will call her Lara, at the first school and she was dating my friend Sarah the entire time I knew her.

Lara identifies as a lesbian, Sarah as a bisexual.

We had hung out, but we were just friendly with each other even though I always felt this little...attraction to her, and I could tell she liked me (as a person/friend/maybe more?). I went back to visit 6 months after moving away and Sarah and Lara were breaking up over the weekend I was there. I have to say I was not disappointed about it. I got coffee with Lara right before heading back, and things were fine (there was another friend with us), but I noticed Lara looking at me kind of...curiously I guess. Like she thought I wasn't paying attention but I could tell she was watching me, and I got all *warm* inside or whatever. And kind of nervous.

I do not broadcast my feelings for women, so it isn't like she has ever heard me say I am bisexual or interested in women.

So now that I've gone home and she is there, we talk a lot. Well I should say text some and snapchat (a lot), and also relay back and forth on facebook/tumblr (where I express and have expressed attraction to women before through blogging). I have these feelings for her, serious feelings about this girl. About wanting to explore my sexuality with her, I mean we were friends and I know how amazing she is. I just don't know if it's right for me to have these feelings 1) because she dated my friend for almost a year and 2) because what if I am in some kind of phase and I mess things up with our friendship?

SO anyway, we kind of have this flirtationship going on. She knows I think about her and I know she thinks about me. We have made it kind of obvious, but I just don't know where to go from here.

I don't know how this relationship would ever work considering we are long-distance, but I am going to visit again this December. I am a little worried about how to act or if I should just go for it. I have never had sex with a woman, or touched a woman privately. I don't know if she is the one I should put that "first-time" pressure on because I love her so much as a friend too. But that makes me think she would understand, and that you shouldn't keep what you feel inside because we are obviously attracted to each other!

Any thoughts/help - very much appreciated.