Tahnee Afuhaamango stepped out of the pool and went home, not realising until later how fast she had actually swum.
The swimming sensation finished the 200m freestyle event in a local competition and then went home to Jingili in Darwin's northern suburbs for a break.
When she returned to Parap pool that afternoon for the rest of the competition, Afuhaamango's mother, Donna Rousham, checked the results and saw that her official time for the freestyle event was 3:38:72.
"I nearly died," Mrs Rousham said.
Afuhaamango's swim was 6.64 seconds faster than the world masters record for swimmers with Down syndrome aged over 35.
She also set an Oceanian record.
Mrs Rousham scrambled to fill out the paperwork, which needed to be signed off immediately by officials who witnessed the feat at the NT Long Course Qualifier on February 6.
"You don't hear of those times," she said.
Five weeks to confirm record
The paperwork had to be passed by Australian authorities before the record could be assessed by the international authority in England.
And just over five weeks later the email has finally arrived to confirm Afuhaamango's record.
Mrs Rousham estimates her daughter has broken more than three dozen world records during her swimming career.
"But this is really special," she said.
"It came out of the blue and Tahnee's a lot older than her heydays.
An inspiration to others
Mrs Rousham said preparing for a record-breaking swim was not a simple process.
"With somebody like Tahnee, you don't want to put that pressure on," she said.
"But [if] you start telling her we're looking for world records, she tenses up."
Margaret Cahill from Down Syndrome Swimming Australia said Afuhaamango was an inspiration.
"As DSSA encourages individuals with Down syndrome to actively participate in the sport of swimming at all levels of competency, it is delighted to have Tahnee striving to achieve personal best times while continuing to swim competitively," she said.
Mrs Rousham said the Down Syndrome International Swimming Association had suffered a blow when its president, Dr Geoff Smedley, died from COVID-19 in March 2020.