Amanda, 27, somberly received the news as she stood in Camden County Superior Court on Thursday, the Associated Press reported.
Both the prosecutor’s office and Amanda’s attorney Jordan Zeitz did not immediately respond to PEOPLE’s request for comment.
After the judge handed down her sentence, Amanda issued a tearful apology, captured in a clip obtained by NJ.com, saying she never wanted her sister to die.
“I know there’s nothing I can say to justify what I did,” Amanda said before completely breaking down. “I just want to make it clear that I never had intentions of taking my twin sister’s life. If I could take back what I did, I would in a heartbeat.”
“Having to live with the fact that she’s no longer alive is devastating,” Amanda continued. “I just want to apologize to my family for putting them through this. I hope that they can all forgive me.”
Zeitz spoke out on behalf of Amanda prior to the sentencing, explaining to Judge Edward McBride that the killing was a result of Amanda suffering from “postpartum depression” and “emotional issues” from pregnancy.
She now is going to remember this for the rest of her life,” Zeitz said in court, according to NJ.com. “The sentence you are going to impose is going to pale in comparison to the life sentence she’s already serving.”
“We would ask that you follow what the family wants — to get her back to them so they can heal quicker,” Zeitz said, NJ.com reported.
Amanda’s family had pleaded with the judge to give Amanda a more lenient sentence, according to the outlet.
In September, Amanda pleaded guilty to stabbing Anna to death during an alcohol-fueled fight in late June.
Amanda admitted her role in her sister Anna’s brutal killing, pleading guilty to a reduced charge of second-degree manslaughter as part of a deal orchestrated by the prosecution.
Amanda was charged with aggravated manslaughter following the fatal June 22 incident.
Police were summoned to an apartment in Camden shortly before 5:30 a.m., arriving to find Anna Ramirez on the ground with blood on the left side of her chest. She had been stabbed once, and was pronounced dead at the hospital an hour later.