uuummm...excuse me "teacher". The statement the woman makes is called hyperbole, not an oxymoron. She is using hyperbole...obvious, extravagant and intentional exaggeration, used to create emphasis or effect.
Your definition of an oxymoron "an oxymoron, a contradiction of sorts: saying one thing while referring to another" is not correct.
An oxymoron is a figure of speech using two contradictory terms such as...living dead, bittersweet, virtual reality, jumbo shrimp or more facetiously, military intelligence.
Where exactly were you a high-school English teacher?