If you're interested and you do nothing you'll be beating yourself up for a long time to come, trust me.
There was this girl when I was in high school who kept doing things that were pretty blatant. I *knew* but I kept second guessing, every time, because I didn't know exactly what to do. I shouldn't have worried about that.
An example of the sort of stuff she'd do. One night we're at a get-together. Some of us, including me and her, decided to sleep there. I took the couch, she took the spare room. She comes down and says the bed is uncomfortable, asks to switch. A little while later, she's back and she says the couch is even worse, and asks to share the bed. Very crafty, she was. But, I'm sitting there thinking "Is this really happening? no ... can't be ... not me ... and even if it is, what should I do? I don't know!" Not a wink of sleep all night. Another time she invites me over to her house, says, "want to see my bedroom?", takes me to her room, and says. "This is my bedroom. My parents are away" and like the big idiot I was at the time I said, "It's nice. I have to go now"
This sort of thing happened on a regular basis over 4-5 year period, til I moved away. She'd even ask me out and say, "it'll be like a date" and I'm thinking "like a date, ok, thats not a date then" but in context of the whole history of everything that was going on, that was ridiculous. I just said that to myself as an excuse.
The thing is, I liked her so much. I thought about her, all the time. I mean, ALL the time. I beat myself up over this for years and years and years, I felt like maybe I hurt her, like she thought I just kept stringing her along or something. I don't have feelings for her anymore, it was so long ago, but I still sometimes worry that maybe I damaged her or something.