My feelings towards her and do you think she likes me?

Okay, so there's this girl, we talk a lot when we get near each other. We laugh, we joke. about everything. The physical contact between us happens every time we are talking,  making jokes, or explaining something to her. She is the only girl I know in school who I know for a fact is genuinely sweet towards me. Everyone else is friendly but just not In my eyes, they seem like inconsiderate assholes who care about only them selfs until I come around. Now my problem is I've grown to liking her, I mean I like the way she talks, laughs, personality, etc.. The full package. But things to me have kind of gotten weird between us. For example here some things I've notice she's been doing. now:  constant physical contact, she only really talks to me, she always stares at me in the hall and in class once I spot her she looks away ( I do it also), she laughs when I laugh or at things I point out or say that aren't really that funny, she acts a way (kind of weird) when i talk to other guys around her, and she's all ways happy when I'm around. I thought this was just being friendly untill when she asked me if i had a  girlfriend then I said no she got shocked/happy, now a couple days later she asked me if i like her if i had any feelings towards her and like an idiot I said no.. Now I'm here thinking should I have said yes?  want to make a move to see  but I don't wanna mess up and look stupid jeopardizing our friendship.... I don't know what to do.. I've also noticed day by day my feelings for her are getting stronger each day that we talk,  I mean I'm always thinking about her for two days straight I've had dreams about her.