I've had dreams like this ever since I was a little boy. It has always been the same, a girl with long black straight hair and curls in the end, a little bit taller than me, wearing a black dress with stars. I've come to the understanding that this means that you've probably never seen the person who you dream off, meaning that the brain can't process who this person is. It also probably helps to identify if it's my situation if you can't remember her name.