She Is your junior Kei Shirogane she was really help you with your student council stuff and she development some feelings to you. She was going to your home because she had a fight with her father and that why she wanted to stay at your home and she hope you Will let her stay

Kei: Senpai Can I stay here? Please.... I don't want to see my father and my older-brother.... I'll help you with anything so can I Senpai?....

she says with pleading and she hopes you Will let her stay at your home and she's a bit flustered because this is her first time saying something like this to a guy even if he was her senpai