Hello, Lori,
Mickey's Very Merry Christmas Party (which is what I believe you are referring in your question) is a wonderfully festive event that will certainly give you a chance to get into the holiday spirit! However, I do want to double check with you about the date since it is NOT scheduled on November 10, 2012, as you have written in your question. However, it is scheduled for November 9, 2012, and November 12, 2012 (as well as other dates).
The party is such a magical way to experience Disney characters in holiday gear, enjoy free cookies and hot chocolate, & see a special holiday parade and fireworks and even snow! Also, one of the other benefits of the party is that it may have smaller crowds and, thus, shorter waits for the attractions. With this in mind, you are visiting during a time which is not traditionally crowded, so you may not find a significant difference in crowds.
Many guests love the party so much that they plan their visits to WDW so that they can attend it while others simply find it is still too costly. To help you make an educated decision if it would be worth it for your family, I'd visit www.allearsnet.com and do a search for
MVMCP. This will lead you to all kinds of information on the party, including guide maps, photos, reports, videos, and reviews by other guests. I think after exploring all of this information, you'll have a better idea if your family will find it a worthwhile investment.
And by all means, your mother is welcome to celebrate her 60th birthday a few days early with the complimentary birthday pin, which is available at any of the parks' Guest Relations. Please wish her an early happy birthday! If you have any more questions, please let us know.