If you dream about your own girlfriend it is very normal and common dream, which can be interpreted only when the other circumstances of the dream are known. Make sure you look into the dream deeper and compare your relationships with your girlfriend in your waking life and in your dream. The dream in which you see the girlfriend being the person that is not our girlfriend in real life, means that you are fantasizing what it would be like to be in relationships with this person. The teenagers have lots of these kind of dreams which is very normal. Sometimes the qualities you like in this person you wish to see them in yourself as well. To dream about your ex-girlfriend, please see the meaning of ex.
Read more about dreaming of Girlfriend in other dream meanings interpretations.