Greetings Kate!
I am so glad that you found us here at planDisney. I am so sorry to hear that you are having trouble getting your tickets linked to your My Disney Experience account. I would be happy to help you troubleshoot the issue, so that you can continue finalizing your plans. 
Stitch likes to wreak havoc in the My Disney Experience mobile app sometimes when trying to link tickets. I suggest that you try again using a computer or laptop. Sign in to My Disney Experience and click the 
My Plans tab. Scroll down to the 
My Plans, Reservations and Tickets section and click on the 
Tickets & Memory Maker tab. Check here to see if your Mouseketeer’s ticket is already linked to their account. If it is not, scroll up and hover over the 
Park Tickets button and click on 
Link Tickets. Re-enter the Ticket ID, confirmation, or Will Call number for their ticket and click next. Follow the prompts to assign the ticket and confirm the assignment. Your ticket should now be linked and you should be able to make your Park Pass reservations. 
You can make your 
Park Pass reservations by hovering over the 
Park Reservations button and click on 
Make a Park Reservation. Follow the prompts to make reservations for your little Mouseketeer for the same parks and dates that exist for the rest of your party. 
If you are not able to link your child’s tickets, you will need some help from a Cast Member over at the 
Existing Tickets team by calling  (407) 934-7639. They will be able to work their magic to get this ticket linked for you. 
You have chosen to visit during the 
World’s Most Magical Celebration. Be sure to check out the new nighttime entertainment created specifically for the celebration. 
Disney’s Enchantment is a spectacular nighttime show combining pyrotechnics along with castle and Main Street U.S.A. projections to bring you a one-of-a-kind experience. It is the perfect way to end a day of adventure in the Magic Kingdom. 
Have a magical time, 
Andrea