Private schoolgirl who stabbed a fellow student in a 'practice' attack before the planned killing of the 'cool group' of girls who teased her is let off on a good behaviour bond and no conviction The teenage girl stabbed the year 12 student in the shoulder in August last year The 15-year-old said she was bullied for years by the 'cool group' It was alleged that she had a list of five other girls who she intended to kill She is placed on an 'obligation' to remain under supervision for eight monthsBy Australian Associated Press Published: 06:04 BST, 3 May 2019 | Updated: 06:04 BST, 3 May 2019 Viewcomments A teenage girl who stabbed a fellow student at an Adelaide private school after being bullied for years by other girls, will not serve any further time in youth detention. The now 15-year-old came up behind her victim in the school toilets in August last year and stabbed the year 12 student in the shoulder. In the Youth Court on Friday she was placed on an 'obligation' to remain under supervision for eight months and had no conviction recorded. A teenage girl, who stabbed a fellow student at an Adelaide private school after being bullied for years by other girls, will not serve any further time in youth detention In sentencing, magistrate Oliver Koehn said he had taken into account the month the girl spent in detention immediately after the offence and the further period of eight months on home detention bail. 'This has been a very difficult period in your life,' he told the girl. 'I believe you've grown up a lot in the last eight months.' The victim, who suffered a one-centimetre wound, was not known to the attacker but had been chosen as a practice target. She pleaded guilty to one aggravated count of intentionally causing harm. The now 15-year-old came up behind her victim in the toilets at the school in August last year and stabbed the year 12 student in the shoulder. In the Youth Court (pictured) on Friday she was placed on an 'obligation' to remain under supervision for eight months and had no conviction recorded A second charge of possessing objects with intent to kill or endanger life was withdrawn. That charge related to allegations she had a list of five other girls who she had intended to kill and that her attack on her first victim was 'practice'. Immediately after the stabbing the girl told her victim, 'I'm sorry, I'm sorry,' prosecutor Paul Tate said in submissions on Thursday. Mr Tate said upon searching the toilet block police found the girl's shoulder bag and inside they recovered a small Swiss Army knife, a black silver flick knife and a pair of scissors. The court heard that in an interview with police the girl had said her actions and plans were motivated by the bullying and insults she had suffered for years. Defence council Yasmin McMahon said her client had done well at school until year seven when some new students arrived. That led to her being excluded from her friendship groups and by 2017 she was suffering significant mental health issues Defence council Yasmin McMahon said her client had done well at school until year seven when some new students arrived. That led to her being excluded from her friendship groups and by 2017 she was suffering significant mental health issues. '(The girl) was experiencing significant bullying by what's termed the 'cool group',' Ms McMahon said. 'She had lost her friendships and her sense of identity in the school.' Ms McMahon described the teenager's actions as completely out of character and more of a 'cry for help' or a way of trying to protect herself from what was happening. Share or comment on this article: All rights reserved for this news site dailymail and under his responsibility