FORT COLLINS, Colo. -- A Wyoming teenager has pleaded guilty to a reduced charge in an accident last fall in which another girl was killed as she "surfed" atop a car.

Karen Buckley, 17, will spend two years in a juvenile detention center after pleading guilty Tuesday as a juvenile to vehicular homicide-reckless driving for the Sept. 6 incident that killed Shailynne Manning, 15. Both girls are from Cheyenne, Wyo.

Buckley, who was driving the car in Fort Collins and was originally charged as an adult, could have faced up to 12 years in prison if convicted. She also pleaded guilty to leaving the scene of an accident, a misdemeanor.

"It's wonderful," said Linda Buckley, Karen's mother. "There's some closure. It's a lot better than 12 years."

Don Manning, Shailynne's father, said he doesn't think Buckley acted intentionally but that she still needs to be punished.

"I hope this teaches her (Buckley) a lesson, and maybe someone can learn from this," Manning said.

According to police, Manning was riding on top of the moving car when it swerved and she tumbled to the ground. Witnesses said Buckley got out, looked at Manning unconscious and bleeding in the street, and asked them to call for help before driving away. She did not notify police and it took them several days to identify the victim, as a result.

Manning died a month later. Buckley still faces charges of motor vehicle theft in Wyoming. Police said the car she was driving at the time of the accident was stolen in Cheyenne.