Most Helpful Girl
I'm going to guess that she's hurting, but doesn't want you to know, or is maybe trying to act like everything is fine just to spite you. Again, this is just a guess.
I don't think that makes you a bad person, I agree with the other commentors that your feelings are pretty natural. You want her to show some feeling of hurt after something you both once treasured just didn't work, and she's not at the moment. I can understand how that would be frustrating.
*cue that one person who rolls in and says "you're 17 you know nothing"*
Most Helpful Guy
Not bad for you to want to know that she's struggling with the breakup. She probably is suffering but is keeping up appearances as we all do.
But if you really are bitter, the best revenge is to be happy without them, as you seem to be experiencing now