The teenager was taken by her mother to Liaisons Executive Retreat, a brothel in the eastern inner-city suburb of Edgecliff, the Wollongong District Court was told on Tuesday.
She allegedly provided services to more than 18 clients over period of 13 hours. Working under the name of "Layla", she charged up to $330 an hour.
The teenager's father reported his former wife to the police, The Australian reported Wednesday.
Though the teenager was distressed by her first experience at the brothel, she had gone back there thrice as she did not want to "disappoint" her mother.
She said said she was initially "excited" and went along with the plan as her mother had always struggled with money.
The woman has pleaded not guilty to the charge of child prostitution.