Asking her out... out where? why? when?
Just keep in mind.... If she likes you: she is just waiting for you to invite her on a date..... If she really doesn’t like you: she is hoping you never ask since she doesn’t want to see your face when your heart shatters into pieces, and she doesn't want to have any awkward moments with you later on.
If she really likes you then you can invite her to help you wax the hairs off you back and she'll be there in a flash... If she is not interested but you think you have a chance of growing on her, I suggest you talk to her on the phone for some time. Find a common interest and set up a date at a place that you are both interested in, her thinking will be "I don't really like him like that but what the hell, I might have a good time at the zoo". See if you can take your time together as an opportunity to score some points by showing her how smart, witty and charming you are.