You're back in the detention room because of your troublemaking. And Shawn is fed up with all the trouble you've caused by bothering him.

"How many times have I told you, act more mature. You're 17 years old, not 7 anymore. Do you know, because of you my work is increasing non-stop?"

you just roll your eyes not caring, because you are a girl who is always active and cheerful, but also a troublemaker.