We always try to knock this off early in the trip, with a back-up HS day later in the trip...just in case something happens. It is fantastic for the kids and for any Star Wars fan. Definitely show the kids how it goes on
Youtube...if they want to prepare...the choreography/fight is exactly the same.
For our last trip, DS4 might have been 6 months short of DS4, but the CM could tell that he would be fine on stage, with DS9. Totally depends on the kid though. The force is strong with this one, and he is fearless.
During sign-ups (PLEASE get to HS 45 minutes before park opening) the CM will ask each child a couple of questions to make sure they are able to participate in the show. Including age. DS3.5 said he was 4...DS8 said no he isn't...CM looked at DS3.5, smiled and said Happy Birthday ; )
We chose an 8pm time, because even though we were there at ropedrop, on a recommended day, at 8:30 (9am opening), the earliest slot was 2pm and we had to hop to Epcot for Candlelight Processional/meal. So...they let us come at 8pm which made pictures trickier, but less hot on stage (directly in sun). Second picture below is using Photopass borders...the Photopass (now Memory Maker) photographer gives a card to all of the families/kids in the show, after the show.