If she is really an idiot and holding up the class by saying all kinds of stupid shit, don't be afraid put her in her place. Just be sure that the rest of the class will be on your side. Just don't be to serious about it, say it half jokingly. Make fun of her for being an idiot. Girls will love it.
Do it when you're sure she is wrong and the rest of the class will agree with you.
Do it when you're sure she is wrong and the rest of the class will agree with you.