I know what it feels like. Believe me. The thing I've learned the hard way, is that all that classic romantic crap is BULL****. That's why you don't see much of that here on this site. I've learned this the hard way. I used to be a complete chump....being nice, doting on her, treating her like a princess etc. And it got me NOTHING.
The truth is, you have to be sexual and manly from the get go. You can't be afraid to constantly escalate. That's the secret of the jerk: he's not afraid to show his sexuality with women. That's why there are so many nice guys scratching their heads while the women they want are getting laid by some total meat head.
ALWAYS remember that girls are sexual creatures too and they want sex just like guys. Society may discourage women being sexual and women are more worried about their rep. But every girl wants to be ravaged by a horny guy. ALL OF THEM.
Here's a little bit of my personal experience from my chump days. I was once in a situation like you. This girl was into me. The interest was there, but I turned into a complete chump. When I finally made a move on her (it was pathetic....I was so nervous), she said she wanted to be friends and that she wasn't ready for a relationship.
Do you know what I found out later? Only a few months ago, she'd been banging a total fvck up. The guy was a jerk, a meat head and he was going no where....he failed out of school. I was crushed. She wasn't ready to get involved in any kind of relationship and yet she was getting it on with a complete loser!?
Now, far down the line, I see my mistake. It wasn't her fault. It was mine. The attraction was there, but I was too much of a b*tch and I didn't step up to the plate. Had I been sexual from the get go and not afraid to make a move, I'm almost certain I could have bedded this girl.
Even the most seemingly innocent girl desires to be banged in some freaky ways. Always keep that in mind. That is perhaps the single most important rule to remember in the pursuit of women. Don't be afraid to get sexual with her (through body language and voice, not words) from the get go. Society, romantic movies and even girls themselves will tell you otherwise but that is all a load of HORSESH*T. It's amazing how bad the information you get in mainstream media really is.
Be a MAN.