Lee Brown, 58, of Gundaroo, was sentenced in Queanbeyan District Court on Friday on six charges including aggravated act of indecency, an aggravated indecent assault, using a carriage service to offend and sexual intercourse with a child under special care.

She was sentenced to 13 months in jail with a non parole period of three months.

The victim, who cannot be named for legal reasons, was a teenage student of Brown's at Yass High School when the offences took place in 2006 and 2007.

The first indecent assault occurred when Brown took several students on an overnight excursion.

During the night Brown climbed into the girl's bed and attempted to kiss her. Court documents state it was the first of a number of times that Brown touched and kissed the victim before the crimes escalted to Brown engaging the student in sex in her empty classroom.

Brown pleaded guilty to all charges, despite her defence counsel telling the court the relationship was consensual.

During sentencing, the victim read her impact statement to the court.

She said the incidents with Brown had left her feeling distressed and suffering anxiety, depression and post-traumatic stress disorder.

"It was a form of hell," the victim said.

She said prior to these events she had a strong circle of friends and was academically minded, but that was taken from her through her teacher's actions. She reported becoming severly underweight and it left her hating her body. She recalled sneaking out of the house to walk the streets at night "to escape the shame."

The victim said she contemplated suicide, delayed her university studies and has experienced trust issues in relationships since.

The victim was supported in court by her family and partner.

Brown apologised to the victim and her family.

"I believed I was in love with her," Brown said.

"I feel awful, I feel dreadful. She was someone I cared about, I cared about her family and I feel like I've betrayed their trust."

Brown told the court of a history of sexual abuse. Her defence team submitted multiple psychologists' reports which diagnosed Brown with PTSD and severe depression leading to risk taking behaviour.

Brown left teaching after the victim contacted her and threatened to tell her parents about what had occurred.

The court heard Brown then became a corrections officer in the ACT, a position she held for more than seven years. She told the court that because of the offences her employment was terminated.

A Justice and Community Safety spokeswoman said Brown had undergone pre-employment checks in 2011 and the directorate first became aware of the criminal allegations in April.

In sentencing Judge Colefax SC said the defence's claims regarding consent of sexual intercourse were "neither here nor there" because of Brown's position as the victim's teacher.

However he said Brown's history of abuse and mental illness "had a direct causal relationship" with her later offending and should be taken into account in the sentence imposed.

The victim broke down in tears as the sentence was read out and was consoled by her mother.