"It's really hard to explain actually. I was in utter shock really and I was quite terrified. It was quite gut-wrenching, really."
Police praised the girl's actions, which her mother said were the result of knowing exactly what to do in such a situation.
"We actually have a code word, so it's definitely something we have talked about at length when she was a little bit younger.
"She is quite proud that she knew something was not right and followed her gut instinct."
Her daughter was still distraught about the approach.
"She is not very keen on being out of my sight too much and not keen to sleep on her own ... she is struggling a little bit."
Police described the man who approached the girl as being in his 60s, of skinny build, with a moustache and wearing a dark beanie, a neon hi-viz jacket, blue jeans and steel-capped boots.
Inquiries were continuing.