from the question i'd say she is around 12-13. or at least just pubescent. anyway the clear disharge and white discharge you describe sounds like common normal vaginal lubricant that changes in consistency throughout your monthly cycle-I'd say you will menstruate soon or have a few times even though you don't mention it. These are normal signs of a healthy vagina! good for you.
here's some info for you.
Billings ovulation method - Wikipedia, the free encyclopedia