I'm a 15 year old girl, and yesterday or the day before I noticed my private area was getting a little dark... I ignored it, but when I looked again today, it was really dark, like a black/ purple color. I'm worried it might be colon or the vaginal cancer (I forgot what it's called)or just something really bad... I am white, I am 115 pounds, and I am 15 years old. Is something wrong? Or is that normal?