9. She is not trendy
Women develop their own sense of style and personality which may not have to reflect the modern trend. If your girlfriend is constantly changing her looks and activities, taking suggestions from the pop culture all the time, you are dating a girl. Their lives revolve too much around outside influences where they have not learned much about their own selves. However, a mature woman knows herself well enough to not go under such trendy impressions. Woman have their own hobbies and passion, they do not need confirmation from others.