Ms Freemantle previously expressed her “deepest sorrow” and said she had “no recollection of what took place” after the deaths of Nuria Sajjad and Selena Lau in Wimbledon, south-west London, on 6 July 2023.
She was first arrested at the scene of the crash at The Study Preparatory School.
Following an investigation, the CPS said Ms Freemantle had suffered an epileptic seizure behind the wheel, which caused her to lose control of the vehicle that then drove into the school.
As a result this meant she would not be charged, it said.
At the time, her solicitor said her epilepsy had “never previously manifested itself” and Ms Freemantle “had always enjoyed good health”.