LGBT: Should I flirt with her or what?

There's a girl in my spanish cl (ridiculously hot) and she's flirting with me a ton. She's definitely interested in me. I don't know if I should flirt back or ask her out, though. I'm a transguy, but I'm not full time yet, so she's thinks I'm a butch girl *sigh* What's a boy to do? I don't want to lie to her, but I don't really know her well enough to know if I can trust her with this. But I REALLY like her.