Chiles began her elite gymnastics career at the age of 12, quickly establishing herself as a rising star. In 2013, she made her debut at the American Classic, where she won bronze in the all-around and silver on vault. That same year, she earned a spot on the Junior National Team, a testament to her early promise. By 2014, she had gained international recognition, winning team gold at the City of Jesolo Trophy and securing silver on vault.

Her junior career was marked by consistent growth and accolades. At the 2016 City of Jesolo Trophy, Chiles claimed the all-around title and added multiple medals, including gold on vault. She also excelled at the U.S. Classic and National Championships, solidifying her reputation as one of the top junior gymnasts in the country.