Quite a bit of backstory to this one. There is, unsurprisingly, this girl - I've worked with her for roughly two years at this point, and we have been friends for almost all of it. About one year ago, she asked me if I wanted to try a relationship. At the time, I was still rather emotionally dull from some bad breakups in the previous years, and .. well, I'm not really sure why else I said no but I told her I did not know right now, and that was that. Unfortunately, a few weeks later a different girl from work sat me down in Applebee's and essentially talked me into going out with her, at least on a trial basis - and a trial it was; as 2 weeks later I broke it off. Now, the original girl who asked me out had stopped talking to me, but I did apologize shortly thereafter and we resumed being really close friends. We remained as such for the next half year or so.
Well, as this year goes on and we become closer friends, I find that I am falling for her quite a lot. Ironically, right about the time I was actually planning on making a move, one of my close friends began talking to her. This 'close friend' and I had some issues ~3 years ago in high school (involving him and my girlfriend-at-the-time - on two separate occasions), but those may or may not be relevant to the story. This is where my long line of errors in judgment reach their peak - she asked me if he was a good guy, and - as I was just starting to trust him myself (I'm a bit too forgiving), told her yes. Fast forward a week or two, they begin dating. Her and I do not talk as much for a while, but she continues to want to be really close friends as she often begins telling me all of their problems (they dated for a total of 4 months, with problems beginning shortly after the first). Well, he breaks up with her and begins bumping uglies with one of the girls he's worked with for several years. She is obviously quite upset, and I, still being one of her closest friends ("[her] best"), keep trying to make her feel better and whatnot. At this point I am feeling quite turd-like, because (a) if I -had- dated her when she originally asked me out, this would not have happened and (b) I gave her the thumbs-up on him, so her getting hurt was inadvertently my fault.
Well, about 3 weeks after their breakup, rumors begin surfacing around our workplace that I like her, including one of her close girl friends telling me that I should. She comes over while my parents are out of town, and SHE has the idea of staying there and getting drunk together. I, of course, agree. Fun times ensue. Nothing major, though pants were removed at one point and we slept in a bed spooning. So, a few nights later, I tell her how I feel. She says that she wants to focus on being happy for herself - which I can understand, she's had 3 major relationships and they've all ended quite badly, and (also) she is still quite hung up on her recent ex. She says everything that happened the earlier night she wishes had not happened and was "leading me on." Bummer. Says she still wants to be friends, though.
And close friends we remain - we still hang out all the time, she's going with me to a wedding and fireworks later this month, etc. We talk all the time, and it's essentially the same except now I make humorous references to how we should date and whatnot. She laughs at them, in case anyone thinks they'd just be awkward. Last night, however, it comes up on a serious note and she says we can't date - she lists how she recently broke up with one of my friends as a reason, and then (perhaps jokingly) says that she thinks if she liked me I would not like her. I take this as she thinks I just enjoy the chase, and it upsets me - as how our friendship works, I tell her this upsets me and that I really do like her and wish she wouldn't write it off like that. Then we joke around some more and then get off the phone. While I originally feared things might take a turn for the awkward, she calls me this afternoon and we chat it up just like normal.
So, now, I present H/A with this gigantic wall of text, and ask for thoughts, opinions, advice, anything. I am 20 and she is 19, for the age-curious. Given a lot can happen in two years, I likely left out many details. If anyone cares enough to need clarification on anything, feel free to inquire. Thanks in advance, this is really wrecking my brain.