This is the second time my crush postponed our date... Should I just ask her to directly tell me if she wants to hang out with me or not?

No, if she postponed it again, cut your losses and move on. Time is a mans most valuable resource and you are wasting yours on her.

You could either ask her directly if she's making up excuses not to go out with you or just leave it and let her contact you. As for the former, if she's interested she'll contact you and at least you won't come across (not that you are) as desperate or a stalker. Totally your call but I would let her make the next move. And if she doesn't, then so be it and move on.

No, you should not ask her directly. Instead, you should pull your head out of yourass and leave her alone. She's not interested, and she's essentially told you twice already that she's not. Get a clue already.

To be honest, I would just ask her directly that if shes interested or not. If she makes a lame excuse then tell her that you don't have time to waste on someone who can't make up their mind. If she has a legitimate reason for postponing the dates then I would ask her for a time and date that is suitable for her so that she doesn't cancel on you.

She's not that interested or you'd have gone out again. Move on.