The mother of the 6-year-old boy who shot his first-grade teacher in Virginia earlier this year was sentenced Wednesday to 21 months in prison for using marijuana while owning a firearm.

Deja Taylor’s son, who has not been identified, shot first-grade teacher Abigail Zwerner on Jan. 6 at Richneck Elementary in Newport News, Virginia, a city of about 185,000 residents known for its ties to shipbuilding for the U.S. Navy.

Authorities have said the boy used his mother's gun and shot Zwerner while she was reading to students in her classroom. Zwerner was shot in the hand and chest and has filed a $40 million lawsuit against the school district alleging gross negligence. She was hospitalized for two weeks and underwent multiple surgeries.

Taylor's son told police after the shooting that he stood on a dresser to take his mother's gun out of her purse, court records said. "My mom had that gun," the boy told officers. "I stole it because I needed to shoot my teacher."

In June, Taylor, 26, pleaded guilty in federal court to two charges: using marijuana while owning a gun and lying about her drug use on a federal form. Taylor also pleaded guilty in August to child abuse in a state-level case for which is scheduled to be sentenced in December.

Taylor's grandfather currently has custody of her son, prosecutors said.

Prosecutors say the case is about more than marijuana use

Federal prosecutors said they planned to seek a 21-month prison sentence and a term of supervised release. They argue in court filings that "not once, but twice someone nearly lost their lives because of Taylor's offenses," citing the shooting of Zwerner and an earlier incident in which Taylor shot at her son’s father after seeing him with his girlfriend in December.

Prosecutors claim Taylor's "chronic, persistent and ... life-affecting abuse extends this case far beyond any occasional and/or recreational use.”

After the shooting in January, investigators discovered 24 grams of marijuana in Taylor's bedroom along with burnt marijuana cigarettes and drug paraphernalia, records said. Prosecutors claim Taylor also smoked two blunts sometime after Zwerner's shooting, and that she failed drug tests while awaiting sentencing on federal charges.

"This case is not a marijuana case," federal prosecutors argued in court records. "It is a case that underscores the inherently dangerous nature and circumstances that arise from the caustic cocktail of mixing consistent and prolonged controlled substance use with a lethal firearm."

Taylor's attorneys: 'Addiction is a disease and incarceration is not the cure'

Taylor’s attorneys had asked the judge for probation and home confinement. They argued Taylor needs counseling for issues that include schizoaffective disorder, a condition that shares symptoms with schizophrenia and bipolar disorder.

“Addiction is a disease and incarceration is not the cure,” her attorneys wrote.

Taylor's attorneys added if the judge decided to impose imprisonment, that she be sentenced to no more than six months.

"Ms. Taylor vulnerably stands before this Court humiliated, contrite, and saddened," the attorneys wrote. "Most important, she is utterly remorseful for the mistakes in her life that led to the horrific shooting of her son’s teacher, who experienced a miracle by surviving."

Earlier this week, two of Taylor's family members submitted letters asking the judge to show compassion when deciding Taylor's sentence.

"With proper guidance and continued family support, I know my daughter can overcome this tough time and go on to do great things," her mother wrote.

6-year-old had history of 'behavior problems'

Court records reveal Taylor's son was "troubled" and had a history of "unpredictable behavior" that triggered previous disciplinary action at Richneck Elementary School.

Taylor told police that her son was diagnosed with "Obstructive Defiance Disorder" and took medication for the condition, according to court records.

In an interview on ABC's Good Morning America in May, Taylor apologized for his actions. "I am, as a parent, obviously willing to take responsibility for him because he can't take responsibility," she said.

Earlier in the week of the shooting, the teacher asked the child to sit down. "He threw his arms up in the air and said 'Fine,' and when he threw his arms up, he knocked her phone out of her hand, on accident," Taylor said.

That led to a suspension, she added.

A legal notice filed by Zwerner's lawyers described the incident differently, saying the boy "slammed" Zwerner’s cellphone and broke it, leading to a one-day suspension. When the boy returned to her class the next day, he pulled his mother’s 9mm handgun out of his pocket and shot her, according to the legal notice.

School officials previously required Taylor's son to attend school alongside a parent as a result of his "behavior problems." The week of the shooting was the first that he was allowed to attend school by himself.

Taylor's son told police that he stood on a drawer of her dresser to take the gun out of her purse. In a search of her apartment after the shooting, federal agents found no lock boxes or other evidence that her 9mm handgun was stored safely.

Contributing: Jeanine Santucci, USA TODAY; The Associated Press