Should you ask your crush who she likes?

This girl I know on my bus was talking to me and another girl on my bus about this boy in sixth form and she says she doesn’t like him but he is in denial about it, anyway after that she said she likes a different boy and now I’m wondering if I should ask her who she likes to see what her answer would be

I don't really see how this can have a good outcome for you TBH.
I'm assuming you're hoping that she says it's you?... If it is, then chances are you would have come up in one of her girly chats with her mates; and if she's OK with you knowing, she would tell you herself, drop some not-so-subtle hints, or at the very least one of her mates would have hinted to you. Forcing her to admit it would be putting her on the spot and would be completely awkward. On the other hand, if she says it's some other cool, sporty type you couldn't possibly compete with, how is that going to affect your self-esteem?
Actions speak louder than words... have you tried to show your interest by flirting etc? If she reciprocates, then there's a chance it might be you; if she ignore it (or keeps her distance), then you know she's not interested.

Ok thank you and yes I do flirt with her sometimes and she does show interest

Then just ask her if she fancies hanging out in the park / at the mall; go bowling; grabbing a "Cheeky Nando's" or whatever teenagers like to do these days. If she say yes, then 'Happy Days', if not, then that's too bad. At least you'll know where you stand, and you can find some other girl to crush on.

A few weeks ago it was snowing and on the bus when we were going back home I asked her if she wanted to go sledging with me just before I got off and she said no I want to build a snowman at my own house or something.