I've been reading over some of the responses to your post. It seems likely that this person could be your dream guide. The idea of shared dreams is really creepy to me, I would have to read up on that to comment on it...
Here are my thoughts: I can't help but think that this character is more than just a dream guide. She has made it clear that she has free will. I am not religious but the label that comes to mind is 'guardian angel'. To me, she sounds like an entity; a positive - in this case - energy that you can't control.