My older is autistic, and my younger is speech delayed. I wouldn't worry too much while at the park, but visuals and social stories will really help. You can make a little story on your computer and print out before the trip. For example:
My name is X, I live with my mom, brother, etc. (photo of you), and we are going to go on a trip to
Disneyland! (Picture)
We'll have to wake up very early and go to the airport (picture), where we'll get on a plane (picture)
On the plane we'll sit in our seats and watch movies and read books. (picture)
Then we'll take the bus to our hotel at Disneyland! (picture)
At Disneyland we'll get to meet some of our favourite characters (pictures), go on rides (picture.) We are going to have a lot of fun, and get to eat churros and corn dogs (picture.)
etc, etc, you get the idea. Some airports are very good and will have a social story on their website like this one:
https://www.phl.org/passengerinfo/Accessibility/Documents/SocialStories.pdf
Again, these are mainly designed with ASD families in mind, but they're super helpful with speech delays as well.