A 13-year-old girl told police “that’s one way to be a celebrity” after stabbing two teachers and a pupil at a school in south Wales, a jury has heard.

As she sat in the back of a police car after the attack, the teenager said to officers: “I’m pretty sure this is going to be on the news so more eyes are going to be looking at me,” Swansea crown court was told.

All three victims survived the attack, which took place during morning breaktime at Ysgol Dyffryn Aman in Ammanford, Carmarthenshire, in April, but one of the teachers was so badly hurt that she had to be taken by air ambulance to hospital where she was treated for a neck wound

At the start of the trial, Judge Paul Thomas KC told jurors that the trial included some “unusual features”. He said that because of her age, the defendant, who is now 14, would be referred to her by her first name and would sit in the body of the court rather than the dock. He also said there would be regular breaks for her.

William Hughes KC, prosecuting, said the girl had admitted wounding the three people and taking a bladed article into the school but she denied three counts of attempted murder.

Hughes alleged that on the morning of 24 April the girl left home with her father’s multi-tool, which he used for fishing. During the school’s morning break, she allegedly approached the deputy head Fiona Elias, described in court as the “primary focus” of the attacks.

The prosecutor said the girl looked at Elias with what the teacher described as “sinister eyes” and appeared to be playing with something in her pocket. Elias asked her what she had in her cargo trousers. The girl allegedly replied: “Do you want to see what’s in my pocket?” and pulled out the silver-bladed tool.

Hughes said the girl told Elias: “I’m going to kill you. I’m going to fucking kill you,” and started to stab her. At one point the girl dropped the blade but she picked it up and attacked a second teacher, Liz Hopkin.

The girl then moved away and allegedly called out to a female pupil: “I’m going to fucking kill you.” She ran towards her pointing the blade at her and stabbed her. Hughes told the jury that the teenage victim “doesn’t recall much of what happened” but remembered being on the ground as the defendant made “a number of attempts” to stab her.

The court heard that the defendant was finally restrained by other teachers, who said she had a “vacant” expression on her face, and the police were called. Referring to the attack on the pupil, the defendant allegedly told an officer: “I stabbed her – oopsies.”

The girl allegedly made her remark about being a celebrity because of the attack and asked an officer: “Are they dead?” Just before reaching the police station, she allegedly asked: “How am I going to face my family after what I’ve done?”

Elias said she had not been aware of the girl harbouring animosity to her, but when police searched the teenager’s home they found a drawing of “Mrs Frog Face Elias”, as well as notes apparently referring to the fellow pupil the defendant attacked suggesting the girl “will burn”. Another note read: “They could die.” She also allegedly wrote: “Death before dishonour.”

Hopkin received leg, chest, shoulder and neck injuries. Elias was wounded in the arm and hand. The pupil who was attacked received an arm injury.

Hughes said the notes, coupled with what the defendant allegedly said as she carried out the attacks, demonstrated that she intended to kill.

He told the jury that several months before the attack, a small kitchen knife had been found in the teenager’s bag by staff at the school after she was seen acting in a “cagey way”. Police were called and she was excluded but allowed back on the condition that her school was allowed to search her bag daily.

The jury was shown CCTV footage of the attack. At the start of it, pupils at the school could be seen playing, chatting and moving around the grounds. A large number of students gathered as the attack took place and watched as the teachers and the defendant tussled.

The trial continues.