– A former middle-school teacher convicted of having sex with a teenage boy will face her full 12-year prison sentence, the Minnesota Court of Appeals ruled Monday.

Karla Winterfeld pleaded guilty to first-degree criminal sexual conduct in October 2018 for engaging in “sexual penetration more than once” with a 15-year-old former student, court documents say.

Winterfeld, 35, appealed the length of her prison term, but the appeals court upheld the 144-month sentence handed down in St. Louis County District Court.

During her sentencing in December last year, Judge David Johnson said that “this case probably has weighed on my mind more than any other case I have ever had.”

“You were his teacher, his mentor ... and you raped him,” court documents recount. “And I just can’t get past that.”

Winterfeld had taught health and special education classes at Lincoln Park Middle School since 2012. In a letter to the court, she apologized to the victim and wrote: “I know there is nothing I can do to take back the pain and distrust I have caused this community.”

She could be granted conditional release after 10 years served, according to court records.