A teenager was sentenced to 53 years in prison Tuesday for killing a new schoolmate who showed interest in boys she had dated.

Judge James Teros called the killing "a murder over nothing."

Sarah Kolb, 18, had been convicted in February of first-degree murder and concealing a homicide in the death last year of Adrianne Reynolds, 16. Kolb's ex-boyfriend pleaded guilty to the same charges.

Kolb read a statement to the judge after witnesses testified that she was a good friend and student who endured a tough upbringing that included being locked in her room as punishment and being harassed because of her bisexuality.

Kolb said such experiences left her numb, unable to experience emotion.

"I was so good at not feeling that I felt no feeling as she died," Kolb said.

Prosecutors said Kolb and Cory Gregory killed Reynolds in Kolb's car over their school lunch hour, then took the body to Kolb's grandparents' farm and burned it.

The pair returned two days later with a third teen and sawed the body into pieces, dumping some remains on the farm and burying the rest in a state park, according to prosecutors.

Defense attorney David Hoffman sought the minimum 20-year sentence, saying Kolb was just 16 at the time of the killing and not mature enough to make sound decisions.

Gregory is seeking to withdraw his guilty plea and stand trial after being sentenced in July to the maximum 45 years in prison allowed under a plea agreement. Gregory, 18, is scheduled to appear in court Sept. 21.

The third teen pleaded guilty last year to concealing a homicide and was sentenced to an indeterminate time in a juvenile detention center.