It's lots of fun! As long as you both paid the registration fee, I wouldn't imagine the instructor would care if you and your mom take turns or not.
Check eBay for decorating tips and other accessories. Cake decorating is a hobby people frequently give up and then sell all their stuff. You may get a good deal!
Happy cake baking!
P.S. Take some of you better looking experiments to work for your fellow employees to eat. Better they gain the weight than you!!!
