Ask her out. Be like this, "Hey, I forgot all my lines, and we need to practice." Then when you go to her house, and pretend like she's helping you remember and stuff. Then at the end joke about it, then ask her out to lunch the next day so you can make up for all the help she did for you. Then the next day talk about something else. Eventually something going to hit, and if she keeps saying yes and stuff, then it means she probably likes you as well. Just don't blurt it out, and take it easy.