Hello, Anastasia. Thanks for stopping by the Disney Parks Moms Panel with your question.
Children under the age of 3 actually don't require theme park admission. So because your child doesn't have a ticket linked to your
My Disney Experience account, there is no way to make him/her a FastPass+ selection. Don't fret though because any attraction that they meet the minimum height requirement and you have a FastPass+ selection for, your child will be able to enjoy that attraction with you.
Because you are traveling with such a young one, I wanted to mention the
Baby Care Centers located at all four of the Walt Disney World Theme Parks. This is a great facility where you can change your babies diaper, feed your baby, or just take a rest from the Florida heat. In the Baby Care Center, there is a nice area with couches and typically a Disney movie playing so your whole family can relax while you tend to your babies needs. Also, Disney has put together a pretty cool
Planning Guide for Parents of Preschoolers that you might want to check out. It highlights must-do attractions with little ones, talks about resort stays and even offers a playlist to get your kids pumped up for their vacation. It's great!
I hope that this helps you. If you have any other questions, please do come back and ask.