She's a girl, and I'm a girl. Should I go talk to her?

Most butch lesbians I have met have been quite shy about showing you they're interested - are you feminine? I'm feminine and find they almost avoid eye contact because they probably think I'm straight and wouldn't be interested - as soon as they find out I am a lesbian though, they pay much more attention then!! So maybe she thinks you're straight which is why she was only giving you little glances? Go back to the cinema, it sounds like you like her, what have you got to lose?! See what she's like the next time you go and see how she behaves around you next time. Maybe ask her for her number :)