Is This Possible? What Should I Do?

I met this girl just about a year ago and fell for her. Hard. But I was naive and very needy at the time. So, needless to say, she wasn't interested. After four uncomfortable months (no idea why it took so long), I got hurt and grew up. I matured heavily and got my life together. For the past six months, we've been pretty close friends. We banter and we tease and we flirt and we also have serious talks sometimes. And I've grown, so I'm much more a man now than the pathetic hopeless romantic I was. High school is ending. We'll be at the same college and all, but lately, something about her responses to me, I don't know. It's nothing painfully obvious, but one of those "is it? could it be?" sorta things. I don't think I'm just seeing things because practically everybody mistakes us for a couple (which can get annoying). She recently (within the last month) got out of an ugly relationship with this creep that none of her friends nor anyone but her could see anything in. (By the by, all of her friends very much approve of me). She has a history of dating creeps, and this relationship really ended badly and she finally sees how creepy he truly is. I don't want to ruin the friendship but also, I can't help but wonder. I haven't liked her for half a year but those feelings are still there. And before, she didn't really know me when now she does. She tells practically no one how she feels, so I'd have to feel it out for myself, but what should I do? I worry about being able to hang over the summer and I wonder how to be sure if she does have these feelings and how to handle it. Six months ago, she made it pretty clear she wasn't interested, but the dynamic is so much different now. I'm no longer the clingy guy who likes her but one of her good friends. Whether or not she's starting to come around, I don't know. Please help.