Why does Sophie want to keep her story about Casey a secret from Jansie?

Sophie wants to keep her story about meeting Danny Casey a secret from Jansie because she fears that Jansie will not believe her and will think her story is just another one of her fantasies. Jansie is more practical and grounded, and Sophie knows she would likely dismiss the tale as unrealistic. Sophie hopes that by keeping it a secret, she can protect her dream and maintain the excitement it gives her without facing any ridicule or skepticism. She yearns for her fantasies to remain her own, untouched by the practical views of others.

This question related to Chapter 8 English Flamingo Class 12th NCERT.
From the Chapter 8: Going Places.
Give answer according to your understanding.