Carol McGlone, 61, now a Cordia worker, was on her way to work when she drove through a red light in Dumbarton Road, Glasgow.
The child - who cannot be named for legal reasons - was with a child minder and started to cross the road when the green man appeared.
But, McGlone didn't see the red traffic light and drove through the crossing, hitting the child and knocking her to the ground.
The schoolgirl was taken to Yorkhill Children's Hospital and suffered a fractured right leg.
McGlone, from Lincoln Avenue, Knightswood, Glasgow, pleaded guilty at Glasgow Sheriff Court yesterday to careless driving on May 31, last year.
She was originally charged with dangerous driving but the Crown accepted her guilty plea to the lesser charge.
Sheriff Marie McTaggart told McGlone - who already had six penalty points - that had she had less points on her licence, imposing five or six points would have allowed her to keep it.
But, she said: "This isn't in my view an offence which falls within that lower category in terms of penalty points - it must attract six or more.
"That would lead to a disqualification which would be imposed by DVLA."
The sheriff disqualified McGlone from driving for three months and ordered that she pay a £320 fine.
When McGlone was cautioned and charged by police, she replied: "I didn't see the red light."
The court was told McGlone works for Cordia services as a carer for children and was on her way to a client at the time of the incident.
It was said on her behalf that the road was busy and the traffic light was obstructed, meaning she couldn't see the red light.
But McGlone accepts she was careless in her driving.