"It's to McKenzie's eternal shame that she drove her daughter there," her barrister, Julia Munster, told the court.
Afterwards, as McKenzie was driving away with her daughter and three of her friends, a rock was thrown at her vehicle.
McKenzie became infuriated and confronted her daughter's rival and her friends.
The 34-year-old returned to her car and was driving away when she saw the girl and her friends crossing a street.
McKenzie swerved into the 14-year-old, with the force of the impact causing her to flip over the car. She suffered fractures to her arms and leg.
Ms Munster said her client then asked if the girl was OK and waited for police and ambulance to arrive.
"She's embarrassed, she's ashamed, and she's sorry," the barrister said.
The prosecution opposed McKenzie's appeal and said her three-month sentence was moderate, even lenient, for such offending.
"At any time from the time she decided to take her daughter to fight another young victim, she could have reflected as an adult that what she was doing was wrong," solicitor Leon Fluxman said.
"She got back into the car with four other young people and could have driven off. Instead, she chose to act in a criminal manner."
Judge Jane Campton agreed three months' imprisonment was a lenient penalty given the circumstances.
"This began as a case about young girls behaving badly and ended with an adult behaving in a worse manner," she said.
- AAP
