Her passenger, 16-year-old Tegan Moyes, was thrown from the car and died in Wellington Hospital from head injuries sustained in the crash.
Police alleged that Rose made and sent two text messages on her phone while driving, within seconds of the loss of control.
Several witnesses took the stand, including Victoria Bunny, who made the first 111 call to emergency services, 2 Degrees expert Teresa Muollo and Rose herself, who said she had sent text messages to her friend and boyfriend while at the Masterton McDonald's carpark, before the crash.
Judge Chris Tuohy said police had not proved the issue of texting. "Police have failed to prove beyond reasonable doubt that the defendant's lack of attention was caused by her being distracted by the making or sending of text messages on her cellphone.
"Given the defendant's clear evidence, it's more likely than not that the crucial texts were sent, as she said, before she left McDonald's."
Judge Tuohy remanded Rose for sentencing on December 12 and for an emotional harm report from the relatives of Miss Moyes to be given.