She did not seem till Season 3 Episode 14. It was written off as a joke.
Cory informed his mother and older brother, “You understand, why cannot you guys be taught from Morgan? She is a superb sister. I imply, she stays in her room, you do not hear from her, you do not see her, and better of all, she stays out of my private life.” When Morgan got here downstairs to stay her nostril in his enterprise, he stated, “Morgan, very long time, no see!”
She replied, “Yeah, that was the longest timeout I’ve ever had!”