Hey, Don't worry about your mom. I think 90% of Disbrides get grief from their families when they first state they are going to get married at DW.
They will get over it and eventually get REALLY excited. If not excited, they will zip it. Most people realize that this is an important day to you and quipping incessantly will push you, who they love, away. Don't worry.
My grandmas are 87 this year and are incredibly excited to go to DW. They plan on lounging in the sun for a week and doing nothing else. HAHAHAA.