Hey there, Adriana!
I can not tell you how much I love this question. I have taken both of my little ones to The Most Magical Place on Earth to celebrate their first birthday and it was such a special moment.
Adriana, I have reviewed the official rules, and balloons are not listed as a
prohibited item in any theme park except for Disney's Animal Kingdom, so you should be fine bringing a small balloon for your photographs.
I actually recommend that you tie the balloon to your stroller. This will make it easier to spot in the sea of strollers. If you do not want to bring a balloon with you, you can always buy a Mickey one when you get to the parks. Once you return home, you could then deflate the balloon and hang it up for the perfect nursery wall decor.
Adriana, if you want to get some amazing professional shots, have you heard about
Capture Your Moment? This private 20-minute photography session with an official PhotoPass Photographer will be sure to get the perfect memory.
Happy birthday to the little Mouseketeer!
Sarah B.