Hi Allison!
The height verification is a super idea but Guests close to the height requirements must be measured at each
attraction where required. In many cases, like you mentioned, they are measured twice; once at the queue entry and then again later on in the queue.
My son almost lost out on his first orbit around the Earth on
Mission: SPACE because he was slouching. I can tell you from personal experience, the Cast Members do a great job getting the kiddos to stand up straight and tall. I know your daughter will be excited and will want to experience the attraction. That combined with some magic from the Cast Members should do the trick. We had the best luck when one Cast Member had my son take a deep breath. He stood up big and tall. The Cast Member gave him a fist bump and we made our way into the queue.
I absolutely understand your question and applaud you for being so thorough with your planning. When my kiddos were so excited about an attraction, but weren't quite tall enough, we quickly moved to the next attraction and redirected back into fun and pixie-dust. There are magical memories to be made. Enjoy every moment.
Thanks so much for sharing your question with the Disney Parks Moms Panel. Please let me know if you need any other information as you plan your magical
Walt Disney World Resort vacation!
Kari