"I didn't want to knock her down or like run over her, I just wanted to bump her, make her mad like I was," Cooper said.
Prosecutors dispute that claim. They say Cooper struck Latoya Crama with the intent to kill her.
But Cooper said she was afraid of the victim after Crama got into her face aggressively after she said hi to her daughter. Cooper knows her daughter because her relative is dating the child's father.
"She was standing on the corner and she waved, and I was like, 'Hi, Leilani' and that was it," Cooper said.
The gesture was enough to outrage the girl's mother, who came up to her and threaten to beat her up. Monday, Crama testified she felt Cooper was taunting her.
But on the stand, the defendant said she was the one who was afraid and trying to diffuse the situation.
"I had the phone in my hand, and I told her like, 'Girl, bye,'' Cooper said. "Like, I don't have no problem with you. I don't even know you, so why am I even going to fight you?"
The defendant broke down crying after her attorney asked her why she left the scene.
"I panicked, and I got scared," Cooper said. "It just looked so horrible, so I left."
Cooper said even she has a hard time watching the video showing the impact. She doesn't know how fast she was going, but said it wasn't that fast because the parking lot was small.
The defendant is facing attempted murder for her actions. Tuesday, she admitted she was also driving without a license at the time.
Cooper will resume her testimony tomorrow and then the case will go to the jury.
EDITOR'S NOTE: The video above is from a previous broadcast.