Lily flower is the symbol for the yuri genre (yuri also just means lily). She said that the class is only available if you have the disposition so she's implying that Aurelia is probably into girls
There's quite a lot of subtle subversion of tropes in this chapter alone and I find it very pleasing.
Shouko's appearance fit the "small animal" type of character, but it turns out she's deeper than you'd expect having actually read some literature which surprises our MC (and in turn us readers...