Can I ask her this, or is it too far?

This isn't a question of rights, or even right vs. wrong. You're confused, and you want clarification. In fact, you should get clarification before your feelings deepen any further than they already have, so that she either has all the information she needs to make a decision or you know she doesn't see things the way you do so that you can stop wasting your time. So, yes, stop carrying around the secret and ask already.