I believe passing the onus onto her may be a bit better. Like asking, how much have you given to the poor in this town, the poor in this school, the poor in this class. She may respond with, I am not rich. Then you can say you make more than every single one of the people in this room, you make make more money than everyone in all of your classes. Her version of rich or yours?
Wish I had your perspicacity when I was in high school.
final update:
today i wrote my essay. unfortunately the question did not allow me to write about the negative affects of unions (it was about andrew carnegie and how well he represented the industrial era) but i did manage to slip in:
1.Who cares if the "robber barons" didn't actually care about the people they donated to?
2.Government achieves revenue through force.
3."Robber barons" enriched the lives of the masses
4.The truth about Standard Oil
Next time the rich people dont care meme comes up ask her if she wants to tax charities.
If I were you I would probably point out the fallacies . She is programmed so debating her won't help. A bit like Madam if all rich people are bad then why do people like Soros and Buffett ask for liberal policies? Why was Obama supported heavily by Goldman Sachs. Why did China abandon communism and India socialism etc.