I also found a good website that might help sway your mom in your direction:
http://www.thesororitylife.com
It's a really cute website in the form of a magazine where you can even take a Sorority IQ test to see how well you know sororities! Let your mom take the quiz in which positive aspects like academics, leadership, philanthropy and sisterhood are emphasized.
Frankly, I love going to parties with my sisters, but at the end of the day the best times we have together are just hanging out and being ourselves.