The first time Gu Qing'an met Xu Niannian was at an Internet cafe. The little girl plausibly said that the guy at the front desk judged people by their appearance, and then she showed her ID card and said he was over 18.
Gu Qing'an thought that if he hadn't seen it with his own eyes, he might have judged people by their appearance.
Later, after they met, the little girl was always careful not to ruin her image, but she didn't know that he already knew it all.