Tamara Broome flew to America after falling for the boy after corresponding with him for over a year.
The boy was reported missing by his parents on 12 June, and was caught while trying to board a flight to Australia.
Broome's flatmate, who asked not to be named, told media that Broome was not trying to kidnap the teenager.
"He is the one who wanted to come here," the flatmate said, adding that Broome believed that the boy's parents had hacked into her email accounts to find out about her.
Under Australian law children aged 17 and under are considered as minors. The relationship began when the boy was 16, and Broome could face two years in jail for her actions.