This 10-second video was secretly taken by the 15-year-old schoolgirl of footballer Adam Johnson before an alleged "sexual encounter".
The unnamed girl said she took the video in Mr Johnson's Range Rover to prove she had met the 28-year-old midfielder, Bradford Crown Court heard.
The footage shows the car dashboard and a recording of the Sunderland footballer.
She told the court: "It was to show that I had actually met up with him. If anyone had asked us, I had the proof there.
"Obviously I was trying to brag about it and show off about it because how many other people could say it had happened to them?
"I thought I was big and I thought I was clever. I didn't see at the time - I feel so stupid now for not seeing but I didn't see at the time..."
One of the girl's friends, however, videoed the footage on her phone.
The recording was taken on 30 January, 2015, at a meeting where the alleged "sexual encounter" that led to the police investigation took place.
On Thursday, the court also heard that Johnson would be a "bit of a paedophile" for going after the girl.
A teenager told the jury she did not at first believe her friend's claims she had had a sexual encounter with the former Sunderland and England star.
But the girl said her friend then showed her "20 times" messages on her phone from the 28-year-old father of one.
The girl, who cannot be identified because of her age said: "At first I thought, 'It's definitely not Adam Johnson, then..."
Kate Blackwell QC, prosecuting, asked the witness, giving evidence via a video link: "Why did you not think it was Adam Johnson?"
The girl replied: "Cos he's, however old he is. And why would he? He's a bit of a paedophile if he's going for a 15...kids and that."
Johnson has admitted one charge of sexual activity with a child and pleaded guilty to grooming the 15-year-old.
He denies two other counts of sexual activity with a child in relation to the same meeting which have been described as "more serious" by prosecutors.Reuse content