Does this girl like me or is she just leading me on?? Please help..?

Okay so I have been talking to this girl for 2 weeks,, We txt every night for about 2-6 hrs, I even did a yoga cl with her! Then I asked her out on sunday for this next weekend, she said yes... Then she txt me monday saying I can't do anything this weekend, of course I was upset, but I was nice and she said thanks so much for understanding. I didn't talk to her tue and then wed rolls around and I see her at the gym.. She smiles and says hey are you doing yoga today? I said no and she seemed sad that I wasn't doing the cl, so at the last second I sneak into the cl, she smiles and say I'm rally glad you are here, after cl I txt her some more tonight, I'm gonna ask her out again.. My question is does she like me or is she just being nice or just leading me on??