Katherine Schwarzenegger felt something was terribly wrong last summer, when she overheard her young cousins chatting about their bodies.

“They’re 8 years old and were talking about how they don’t want to be fat and how they want to be ‘sexy,’” says the 20-year-old daughter of California Gov. Arnold Schwarzenegger and journalist Maria Shriver.

It wasn’t the first time Katherine had heard the girls and other young friends discuss body-image issues. She, herself, had struggled to maintain her self-esteem under media and public scrutiny.

Now a junior at the USC Annenberg School for Communication & Journalism, Katherine eventually tackled her body-image issues and developed self-confidence—and she shares her hard-earned wisdom in a new book, Rock What You’ve Got: Secrets to Loving Your Inner and Outer Beauty from Someone Who’s Been There and Back.