But prosecutors and her lawyers are arguing over whether she intended to kill the man.

Jamie Lee Dolheguy was 18 when she met the man on dating site Plenty of Fish in July 2018, the Victorian Supreme Court was told on Wednesday.

After exchanging six messages, Indian-born student Maulin Rathod went to Dolheguy's home in Sunbury.

Her online profile outlined she was dating for the first time, had borderline personality disorder, suicidal ideation and extreme fetishes including bondage.

"We'll do whatever you want," Mr Rathod told Dolheguy via text before he drove over.

But while the 24-year-old was on his way, the teenager went online and searched "I'm going to kill someone tonight for fun" and "I will kill someone tonight, I want to commit murder".

She visited a website called "ten steps to commit a murder and get away with it" before he arrived.

Dressed in a "cosplay" outfit, Dolheguy discussed choke play with her victim, prosecutor Patrick Bourke told the jury.

The teenager attacked Mr Rathod "under the ruse of a sex plot", he said.

"She killed him under this ruse or pretence they were going to engage in consensual sexual activity that would involve choke play," he said.

Dolheguy choked her victim before wrapping a USB cable around his neck and strangling him, the court was told.

"He was in the wrong place, with the wrong person, at the wrong time," Mr Bourke said of the victim.

It is not disputed that Dolheguy killed Mr Rathod, but whether it was her intention to kill or very seriously injure him.

"What is disputed is that she had murderous intent," her lawyer Sharon Lacy told the jury.

Hours before the murder, Dolheguy messaged a support worker and told them she had forgotten her medication.

"I feel really sick with bad temptations," she texted them.

She was told to put in place her "emergency plan" but hours later she called police.

"I think I've killed someone. I didn't want to, but I did it," she told police.

Mr Rathod was taken to hospital, but died the following day.

Ms Lacy said the young woman had a difficult upbringing, experienced extreme abuse and had two full-time carers from the age of 14.

The full-time care was withdrawn when she turned 18 and she lived alone.

"Ms Dolheguy was so damaged, and her mind was in such chaos that you couldn't be satisfied she had murderous intent," Ms Lacy said.

During the trial openings Dolheguy, now aged 20, sat in the dock using colour pencils and appeared to be drawing.

The trial will continue before Justice Peter Almond on Thursday.

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Australian Associated Press