Hi Claire,
Welcome back to the Disney Parks Moms Panel! I can imagine the excitement in your household as your Walt Disney World Vacation gets closer!
If you did not purchase a vacation package, you will need to link your tickets to your
My Disney Experience Account. To do so, go to My Disney Experience and click on "My Reservations and Tickets," then click on "Link Tickets." You will need to assign each ticket to a member of your family. As long as your sister has a My Disney Experience Account linked to yours and everyone has valid theme park tickets linked in My Disney Experience, your sister should be able to make all of your Fast Pass+ selections. If your tickets are valid for a different number of days, then she will only be able to make Fast Pass+ selections for the number of days each person has valid theme park admission.
It also sounds like you have already purchased or are considering purchasing Memory Maker. As long as you purchase Memory Maker while logged into your My Disney Experience Account, it should automatically link to your account. If for some reason it does not, you can go to My Disney Experience, "Link Reservations and Tickets," then click on "Link Memory Maker."
Before your Fast Pass+ selection window opens, I suggest you prioritize the attractions you want to experience. Be sure to check the height requirements on the
attractions pages. When our girls were 5-years old, we took them on their first trip to the Walt Disney World resort and one of them was barely 40 inches tall. She jumped up in the air when the cast member confirmed that she met the height requirement for Soarin'- happy moment.
Claire, I am sending pixie dust your way hoping your family has a great time!
Magic, memories and Minnie Mouse hugs,
Donyell