Although she was just 16 years old at the time, Sadie said she took the girls' behavior in her stride.

"I could have totally lost it over the comments people made and the icy looks they gave me," she said. "But I didn't. God had been training me all my life...to be strong and confident."

The reality star also discussed the appearance and perceived attitude of the other girls.

"To me, they all looked about six feet tall and were super skinny," Robertson wrote. "They were pretty obsessed with their weight, so instead of having snacks or treats, they smoked cigarettes and drank coffee... They were quiet, and they seemed either sad or kind of angry.

"They cared way too much about their outward appearance— and confidence is an inside thing," the "Dancing with the Stars" standout explained. "If people try to become confident by trying to make themselves look better or feel better, they will never get there."

"Live Original" is available in digital and physical retail stores on October 28. The release is Sadie Robertson's first book.