Hi Agustina,
How special to be celebrating your mom's birthday at Walt Disney World Resort! If there is anything that you can do to convince her to wear the happy birthday button, try to do so. Plenty of adults wear them! My husband wore one for his birthday,and we are traveling to Walt Disney World to celebrate my 39th birthday soon, and I absolutely plan to wear one! It is so much fun to hear cast member and other guests wish you a happy birthday all day long, and sometimes cast members are able to give you a "magical moment," such as a cupcake, when they see you in that pin. Maybe it would make your mom feel more comfortable if the rest of your family also wore pins, such as the "I'm Celebrating" pins. All of these pins are available free of charge at Guest Relations at any of the theme parks.
If your mother really does not want to wear the pin, there are other options for you. First of all, be sure to note on any reservations, including your resort and any dining reservations, that you are celebrating a birthday. They may be able to make some magic happen. As with the pin; however, never expect that anything extra will happen - and then if it does, it is extra magical! You might also consider working with
Disney Floral and Gifts, who can put together a personalized gift for you mother. Once you have browsed their website a bit, I suggest calling them at (407) WDW-GIFT (407-939-4438) to speak with a Dream Maker who can help you personalize a gift for your mother. Another idea is to call the Disney Cake Hotline at (407) 827-2253. The cast members there can help you to customize a cake for you mother and have it delivered to most table-service restaurants at Walt Disney World.
I hope that this gives you some idea for celebrating your mother's birthday at Walt Disney World, Agustina. I am sure that she will have a magical celebration simply by being at Walt Disney World with you!