A teenager who police say stabbed a woman 21 times in the fall of 2015 in Hyde Park agreed Friday to plead guilty to attempted murder and serve 15 years in prison, the Travis County district attorney’s office said.

Pearl Moen, 19, who lived a few blocks away from the young woman who she attacked, wrote about the thrill of the stabbing in her diary, police and prosecutors said. The attack happened Nov. 14, 2015, just after 7:15 a.m.

Moen never posted bail and never left the Travis County Jail since her arrest on Feb. 28, 2016, records show.

Attempted murder carries a maximum penalty of 20 years in prison.

The victim told the Austin American-Statesman in 2015 that her right lung collapsed and she lost a dangerous amount of blood from the attack, but she was undergoing physical therapy as she recovered.

She and a friend had been relaxing outside on a blanket that morning, she told the Statesman. When her friend went back to his apartment, she took a moment to relax and closed her eyes. Then, someone suddenly attacked her with a knife.

She said her attacker smiled as she stabbed her.

“Moen was 17 years old at the time of the crime and had a history of drug use and psychological issues, but no criminal record,” the DA’s office said in a statement.

The victim spoke directly to Moen after the plea, saying that she was glad Moen stabbed her rather than a child, an elderly person or someone who could not defend himself or herself, the DA’s office said.

According to Moen’s arrest affidavit, detectives found what they believe is Moen’s diary, which contained the following entry:

"I stabbed an innocent woman to death earlier today – technically yesterday since it's 1 a.m. It was absolutely fantastic. Murder gives me a high unlike any other. It feels like this crisp unreality, flashing and sparkling, adrenaline and shock, fight or flight mode. How do I even go about describing it. The whole thing was unreal. I'm so proud of myself. I stabbed her like 20 times. Maybe more. I wasn't counting. She screamed and grabbed at me, saying, 'What the (expletive)?! Help. Leave.' ... For now, I should explain why. Other than the fact that I'm a homicidal psychopath. I have a deep hatred towards people right now. ... Yesterday I lost my other gold ring I've worn all my life on a chain around my neck as it was ripped off by a girl I was murdering. Fate is weird."

On the day of the stabbing, police said they found a gold ring partially covered in blood on the sidewalk near the victim.