Welcome to Dreamviews!

That sound likes a pretty cool dream you had. What your describing can be 2 things:

1. A dream character your mind just made up , even if you didn't know her. I heard that every person you have seen in a dream, you have once seen in real life at some point. I'm not sure how true that is.

2. Shared Dreaming. There is a whole debate on whether this is even real or not and I don't want to get into it too much. Basically trying to answer, can we really enter other people's dreams or not. If you look through the forum you will find a whole shared-dreaming section.