Hiding Behind Looks

I noticed that a few books I'm reading portray girly girls as sluts because of what they wear and how they act but they also have a story.

Amanda Evans is in her last year of high school and is looking to live it to the fullest. The year before, she was known as geeky and wasn't really social. Now, she has bleached hair, wears makeup, and knows how to put an outfit together.
Everyone sees her as girly, but these things are what keep her going because in the end, do we really know people's lives?