Emotionally attracted but not sexually attracted to this girl

I'm 17 years old and have always identified as straight in the past. I've only dated guys and had sexual experiences with guys. About 7 months ago, I met this girl… I'll call her Emily. It's weird, because I don't know anything about her (besides what I've learned from stalking her Facebook page), I've talked to her casually maybe once or twice, we aren't friends or anything, but I feel this strange pull towards her. I want to say it's a crush, but there's one pretty huge part missing… The sexual attraction. I am physically attracted to her, yes, but the physical attraction is more associated with the feeling I get from her than the visual appeal itself. Don't get me wrong - she is pretty - but like I said, the attraction is mostly associated with the feeling I get from her than anything else. When I've had crushes on guys in the past, I fantasized about being with them sexually, but when I try to do that with Emily, I feel kind of turned off. That is what is kind of unusual.

I certainly have the capacity to be sexually attracted to women. I've fantasized about having sex with women (it may be worth noting that the objects of my lesbian sexual attraction have all been insanely gorgeous actresses). But with Emily, doing so feels somehow wrong. I don't know for sure why, but I think it might be because fantasizing in that way makes me feel guilty since she is a little younger than me. (Only actually a few months younger, but because of the birthday cutoffs and whatnot, she is in the grade below me which makes the gap feel bigger.) It's also worth noting that when I have been sexually attracted to women, it has stemmed from an emotional place, which is not always the case for men. For example: I apologize in advance if this is crude, but I can be aroused by naked male parts, regardless of who they are attached to, and I am not really aroused by naked female parts in the same way. When I am aroused by womens' bodies, it's more of an emotional thing… Like I am seeing something about them that is personal and private. It's the closeness.

I feel very emotionally attracted to Emily, though. I think about her CONSTANTLY, I get nervous when I'm around her, I look at her whenever I get the chance, long for the next time I know I will see her, I fantasize about being close with her and having a secret relationship with her and kissing her and hugging her…

I know this was long, so thank you for reading. I guess my question is just… What do you think about this whole situation? What's with this whole emotional attraction but not sexual attraction thing? Does this make me lesbian or bi or is it maybe just a phase? And does the fact that I've only been sexually aroused by ridiculously attractive celebrities and not regular women mean that I'm just like any other human who is attracted to extremely attractive people, and not actually bi, or what?