Clearwater, Florida (CNN) -- A 20-year-old Florida woman involved in a love triangle was found guilty Friday of second-degree murder for fatally stabbing her romantic rival in a fight 15 months ago.
Rachel Wade convulsed in sobs as the bailiff read the six-person jury's verdict, which carries a sentence of 20 1/2 years to life in prison. She dabbed her eyes with a tissue, chewed on her lips and brushed her long blond hair away from her face, tucking it behind her ear. Then, accompanied by a guard, she stood and walked out of the courtroom, to be taken to Pinellas County Jail.
Wade testified Thursday that she stabbed 18-year-old student Sarah Ludemann only after she herself was hit three times in the head during the fight. Ludemann, who was unarmed, died at the scene after being stabbed twice in the chest.
The jury didn't buy Wade's claim that she acted in self-defense -- returning its verdict after just 2 1/2 hours of deliberation.
Inside the courtroom, Charlie Ludemann, the victim's father, breathed deeply upon hearing the verdict, then turned to his wife and nodded.
Wade did not appear to look at the dozens of teenagers who sat on her side of the courtroom.
"There's no doubt that both of these families will be devastated for the rest of their lives," defense lawyer Jay Hebert told reporters after the verdict.
He said his client had insisted on a trial and had rejected suggestions she approach the prosecution to discuss a plea bargain. "She wanted to testify her side of the story, and I commend her for that," he said. "The jury made their call."
Hebert described himself as "somewhat shocked," given the short deliberation. "I just didn't think it would be that way," he said.
Wade, at 5-foot-4 and 110 pounds, had no criminal record and testified that she had never been in a fight before. She said she headed to a friend's house with a knife only after being told that 5-foot-9, 166-pound Ludemann was heading to her home.
Instead, Ludemann and her friends found her outside the friend's house. "I didn't think they would attack me if they saw the knife," she said.
She testified that she swung the knife after being hit three times but wasn't aware she had stabbed Ludemann until one of the victim's friends told her so.
"I didn't know where she was stabbed or how severe it was," Wade said. "I was scared."
During cross-examination, Wade -- who worked at a restaurant -- acknowledged Thursday having thrown the knife into a neighboring yard, but said, "I didn't know what happened, and I didn't want anybody else to get hold of it."
Prosecutor Lisset G. Hanewicz was unpersuaded. "Why get rid of it if you are acting in self-defense?" she asked Friday in a closing argument. "She wanted to get rid of the evidence. She showed no remorse. She knew she stabbed her."
Animosity between Wade and Ludemann had gone back months -- and it centered on their mutual love interest, Joshua Camacho, then 20.
In an August 29, 2008, voice mail, Wade can be heard saying, "I'm guaranteeing you I'm going to ... murder you," and in another, she tells Ludemann, "You are a f***ing fat b**** and I'm going to f***ing kill you, I swear on my life," Wade said in a voice mail left for Ludemann.
Another one said, "Josh may have played me, but, b****, I'm going to play your a** out too, so watch."
"Those tapes were our most difficult obstacle," Hebert told reporters afterward. "Those tapes were very powerful."
Wade testified that Ludemann had left similar messages for her, but that she had deleted them.
Camacho testified Thursday that he considered both women "friends with benefits" and wasn't seeing either one exclusively at the time.
"In Session's" Lena Jakobsson and Beth Karas contributed to this story.