how to talk to the girl i like?

I don't know if I like this girl. Sometimes I can't stop thinking about her, and others I feel like I don't want to be with her. I feel this way from her too, as she sometimes ignores me and sometimes can't avoid smiling when she sees me. I think this thing of liking and not liking is due to the fact that I don't know her 100%. We talk abou alot of stuff, and she even tells me things she does not tell anybody else (not even her closest friends), and we smile and sometimes flirt to each other (even though I'm really naive at that). But I don't feel 100% myself around her, I cannot be who I really am. This might be because we met recently, and we don't spent alot of time together, but when we do, it is either great or awkward (mostly awkward). Only very few times has it been successful. Should I try to be her friend? How sho? I make her smile, I've noticed, with my personality. Should I make her smile, or try to be flirtatious and romntic. Should I aim to be a friend or her boyfriend? I am really confused, I can't stop thinking of her. I want to be closer to her but don't know how. Could you please tell me how to be closer to a girl? Thanks, I would really appreaciate it. P.S.: I am really introverted, so I cannot tell her how I feel, what I feel, etc. Can this be why we don't connect 100%, because she tells me everything and I can't?