Miss Wufu made up a story that seemed true yet fantastical. If anyone were truly intent on investigating, they would naturally find out that she indeed lived with her mother by the mountainside. But as for whether she really encountered a crazed old man, who knows?
Isn't it said that some hermits who live outside the world's conventions often act unpredictably and like to venture deep into the mountains and forests? Living by the mountainside, perhaps Miss Wufu really received some kind of fate and thereby learned a set of skills, which would be hard to say.
Otherwise, how could one explain her various skills at such a tender age? It surely couldn't be as she said, that she simply woke up one morning with the knowledge, right? Which story is more believable is something everyone is well aware of.