M[19] can't tell if F[19] is interested.

I'm usually good at telling if a girl is interested or not, but for some reason I can't right now. Also, I'm pretty sure she knows I like her, I've made it pretty obvious by accident I guess. We hang out for at least a couple hours a day (sometimes much longer) 4-5 times a week. We get lunch together sometimes and go for walks and stuff like that.

When we're with a group of people sometimes she tries to sit on my lap or something like that, but I don't really let that happen because I dont want to start entering friend territory where something like this wouldn't mean anything.

Another, problem is she is much more attractive than me, however I don't think she cares about that. If I wanted to make a move how do I go from hanging out with someone on a regular basis to asking them out on a date?