This sense of trouble Mei Mengzhen felt was still about her studies.
She had drunk Spiritual Spring Water, which boosts memory, so her memory is really good—no doubt about that.
If she just glanced at something and remembered it, she'd get it really clearly at that moment, but would forget after a few days. If she looked at it carefully, she would remember for a long, long time. So, sure, her memory improved, but her original intelligence stayed the same.
In other words, she remembered everything she's seen in her textbooks, but her IQ was still at where it always was. She got the material, but she didn't necessarily understand it.
With the intelligence of a thirty-something, she couldn't manage to truly master high school senior topics and use them flexibly, so even with all this knowledge, there was still no guarantee she'd get into a great school.
