A man accused of murdering Lucy McHugh once led a 14-year-old girl to have sex in the woodland where the schoolgirl's body was found, a court heard.
The woman told Winchester Crown Court she met Stephen Nicholson in 2012 and was reluctant to have sex with him outside but "he kept persisting".
Lucy, 13, was found stabbed to death near Southampton Outdoor Sports Centre in July 2018.
Mr Nicholson denies sexual activity with a child and murdering Lucy.
Jurors heard that the woman, who cannot be named, contacted Mr Nicholson in June 2012 - when he was 18 - to ask him to tattoo her.
She said he messaged her in the week before they met and the chat became "flirtatious", with them agreeing to meet for sex.
"I was 14, I was stupid," she told the court.
She said they were on one of the football fields at the sports centre when she told Mr Nicholson she did not feel comfortable having sex outside.
He suggested going into the woodland, the woman said, and "seemed to know exactly where he was going".
"He kept persisting, he didn't force me but he was very persistent until I agreed," she told the court.
She said it was "very awkward" afterwards as they walked back, with Mr Nicholson giving her and her friend a tattoo later the same day.
The woman told the court her mother found out about the tattoo two weeks later and gave a statement to police about being given it underage.
James Newton-Price QC, defending, said the statement only mentioned the tattoo and made no mention of the sex.
The woman told the court she had not said anything about the sex because she did not want to get into more trouble.
Jurors have previously heard that Mr Nicholson, 25, occasionally lived with Lucy and her mother as a lodger in Southampton.
The care worker, formerly of Mansel Road East, Southampton, denies murder, three charges of raping Lucy when she was 12 and two counts of sexual activity with a child once she had turned 13.
The trial continues.