The grandmother's injuries were originally thought to be non-life-threatening.
A 14-year-old girl learning to drive stepped on the gas instead of the brake and accidentally hit her 81-year-old grandmother, who later died, police said.
The woman was identified as Antonia Ramirez De Mendez of San Jose, Calif., according to the San Jose Mercury News.
Read: Grandmother, 75, On Her Way to Church Killed with 2 Grandchildren During Police Chase
The girl, who was not identified because of her age, was getting a driving lesson Saturday from her father, Sgt. Enrique Garcia of the San Jose Police Department told Inside Edition.com.
After driving around the mobile home park where they live, the girl pulled into the family’s parking space and stopped the car, police said.
But she then accidentally stepped on the accelerator, striking her grandmother who standing nearby.
The woman was taken to a nearby hospital with what were considered to be non-life-threatening injuries, police said.
But at about 3:30 a.m. Sunday, the grandmother died. The incident is under investigation.
Watch: Family Says 92-Year-Old Grandmother's Wedding Ring Stolen in Hospital
