"She rode straight into a nearby fence. The distance was about 15 to 20 metres between where she went past me and hit the fence."
Sarah was declared dead at the scene.
Police investigated the incident but nobody was charged in relation to it.
Coroner na Nagara said it was "entirely possible given her age and inexperience she simply panicked, and lacked the maturity and presence of mind to respond appropriately to the situation she was in".
There was nothing to suggest there had been a lack of care or oversight on the day the crash happened, she said.
"But it is noted that these vehicles do pose significant risk to young riders when things go wrong."
It was a "sad reminder" of how quickly and tragically things could go wrong for such young riders of motorised vehicles, Coroner na Nagara said.