Feeling very distressed and need advice

There's a number of things going on with me lately. Let me start by saying that I am a pretty private person; some would say "shy", but I'd put it as "reserved". I am a freshman in college and am having a good time. I'm an honors student and really prioritize my academics, but I'm socializing well and have started to warm up to people. My roommate (random assignment) and I are getting along really well and are becoming good friends (I'm not attracted to her, just to clear that up). She doesn't know I'm not straight; I don't think it would be a problem at all, but I'm still afraid to tell her. My best friend here (very religious and against LGBTQ) has no idea...neither do my parents. I did tell my mom that I thought I was bisexual back when I was 13 or so, and she was shocked, very unhappy, and didn't even seem to believe me. My dad would probably be okay with it or just want me to wait before making any big assumptions. I've always said that I never wanted to be in a relationship, which was a lie. I just wasn't especially interested in a relationship with a guy.
But even with all that, I have difficulty striking up conversations with people...especially people I like. My problem is that I get BAD crushes on girls I don't know. Like, at-first-sight-but-really-intense, can't-even-look-at-her types of attraction. I'm interested in a casual friend in one of my classes, who is straight. As far as I know, anyway.
I'm a member of the GSA group on campus, which had its first meeting this week. I loved it and am so glad it exists, and I'll definitely keep attending. But I'm still so afraid to show anyone I like that I'm interested in them. I have no idea how to flirt (really hate that word). There's such a lack of confidence in me that I really can't get over my insecurities and do what I want to do. For instance, there's a girl in the group (who actually is a lesbian, and single) who I am crushing on BIG time. It's actually an enormous pain in the ass because I know I'll never be able to talk to her, or anyone, it sometimes seems.
I'm having a lot of trouble with this. I really want to be able to have a relationship, and it's been weighing on my mind. On top of that, although I'm currently identifying as bisexual, I'm starting to question even that. I literally don't even notice men the vast, vast majority of the time. I did get crushes on some boys back in...well, middle school, and those occurred basically because they showed some interest in me (even just friendly interest) and I liked the idea of being liked. Those attractions, if they even were attractions, were nowhere near the way I feel about women now. Literally, I think Michael Fassbender is extremely sexy and that's it.:dry: I kind of wish I were kidding. I can't imagine doing anything with anybody else non-female. I don't know what I am, and although it doesn't bother me that I might be gay after all, it's kind of a lot to take in.
I guess I just need advice as to my real sexual identity and what to do about the debilitating need for distance that I have. I'm afraid I won't be able to have a relationship, ever, and it honestly scares me because I want to. Thanks for taking the time to read this mess.

 

I used to think that might be the case, but I know now that it isn't true. I am definitely sexually attracted to women. I think the reason I thought I didn't want a relationship in the past was because I sub-conciously didn't "allow" myself to consider the idea of being in one with a woman, which sounds MUCH more appealing to me than a heterosexual relationship. I interpreted lack of general interest in men as lack of interest in anyone.