Bristol Palin's only 20, but her memoir is chalk full of interesting stories and details about her life so far. In the book, Not Afraid of Life: My Journey So Far, she trashes ex Levi Johnston and details the first time they got intimate and much more.

Bristol reveals that the first time the former couple had sex, she was drunk on wine coolers while camping. Then, the two promised Bristol's mom Sarah Palin that they wouldn't do it again until they were married. Clearly, that didn't happen -- they had a son before things went south between them.

Bristol describes Levi in the book as a guy "who cheated on me about as frequently as he sharpened his hockey skates" and refers to him as a "gnat." And, that's just the beginning.

The 20-year-old tells her side of the story in this detailed read, and Levi will tell his side in Deer in the Headlights: My Life in Sarah Palin's Crosshairs, which arrives on shelves this fall.