Robyn Oxley was asleep in her St Marys residence when a Jeep Grand Cherokee driven by Batoul Sleibi El Dirani barrelled through the front of the home on October 8, 2022.
The force of the impact threw the grandmother out of bed, through her back window and over a fence.
She was found in a neighbour's backyard by police, who unsuccessfully tried to revive her.
El Dirani had a five-month-old baby in her car as she travelled at up to 115km/h down a road with a 50km/h speed limit, Penrith District Court heard on Monday.
The 30-year-old's SUV did not stop or turn at a T-intersection, instead travelling straight and colliding "with some force" into the gutter, the court was told.
It continued through an arrow sign before hitting a tree and a bicycle in Ms Oxley's front yard, and then ploughed into the home.
"The vehicle essentially travelled through the front wall of the house, through the front bedroom and continued through the house to the rear bedroom where the deceased Robyn Oxley was sleeping," the crown prosecutor said.
El Dirani is accused of grabbing a baby from her car and fleeing the scene, walking down the road before she was intercepted by police.
"As a result of her unusual and erratic behaviour, she was ultimately conveyed to Nepean Hospital, where she was scheduled involuntarily," the crown prosecutor said.
After taking anti-psychotic medication, El Dirani was discharged in a stable condition, the court heard.
On Monday, Judge Miiko Kumar heard both prosecutors and defence lawyers had agreed the 30-year-old had a mental health impairment at the time of the crash.
Aided by an Arabic interpreter and supported by her husband, El Dirani pleaded not guilty to one charge of aggravated dangerous driving occasioning death while driving more than 45km/h over the speed limit.
She also pleaded not guilty to two back-up charges of dangerous driving occasioning death and failing to stop and render assistance after a fatal accident.
The pleas were met with scoffs in the courtroom from Ms Oxley's family members.
Judge Kumar was asked to deliver a special verdict, in which the details of the case were proven but El Dirani would not be held criminally responsible.
The crown prosecutor said evidence from two psychiatrists supported this proposed verdict based on observations of the young wife in the lead-up to the collision and in its aftermath.
"She did not know the act was wrong because of her highly disordered mental state at the time," the prosecutor said.
Defence barrister James Trevallion conceded his client voluntarily caused the collision.
The hearing has been adjourned for judgment on Tuesday.
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