Michelle Carter, who was convicted in 2017 of sending her teen boyfriend texts which encouraged his suicide, was ordered to prison Monday to begin her 15-month sentence.

According to NBC News, a Massachusetts judge ruled that Carter, 22, must immediately report to prison despite her defense lawyers arguing she stay free as her case is appealed to the U.S. Supreme Court. Carter was 17 when she demanded her boyfriend, Conrad Roy III, 18, to “get back in” his truck as it filled with carbon monoxide fumes that ultimately killed him.

Fox News reported that Carter wrote to Roy, “You can’t think about it. You just have to do it. You said you were gonna do it. Like I don’t get why you aren’t. You keep pushing it off and say you’ll do it but u never do. It’s always gonna be that way if u don’t take action.”

Last week, the Massachusetts Supreme Court upheld her involuntary manslaughter conviction for Roy’s 2014 death.

“After she convinced him to get back into the carbon monoxide filled truck, she did absolutely nothing to help him: she did not call for help or tell him to get out of the truck as she listened to him choke and die,” Supreme Judicial Court Justice Scott Kafker wrote in the court’s opinion last week, according to Fox News.

In July, Carter’s legal team pushed for her conviction to be overturned, claiming her text messages were protected by the First Amendment, according to the Boston Herald.

Carter’s attorney recently told ABC News, “This case legally is not over.”

[Featured Image: Michelle Carter/AP Photo/Charles Krupa, Pool, File]