I'd be inclined to agree with those here who have speculated that she was flirting, but you failed to ask her out before she either got bored, or felt that you weren't interested and that continuing to flirt would just be embarrassing for her.
If the latter is true, and you like her, you still have a chance - but you're going to have to make the first move. If you do, and it turns out she just got bored, then you have to chalk it up to experience and move on.
It really depends on how keen you are on her, really - if you're keen enough you could re-ignite something, and if the idea is still fairly new and uncertain to you then you can brave rejection if it happens.
If the latter is true, and you like her, you still have a chance - but you're going to have to make the first move. If you do, and it turns out she just got bored, then you have to chalk it up to experience and move on.
It really depends on how keen you are on her, really - if you're keen enough you could re-ignite something, and if the idea is still fairly new and uncertain to you then you can brave rejection if it happens.