That the Emperor was also a Darth.
That Vader was in his 40's and Alec Guinnesses Kenobi was in his 50's going by the prequels.
The the Empire was only as old as Luke and Leia.
That a Death Star takes 20 years to build.
That Jedi's are dull celibates.
That the Force and the Jedi would become stuff of ancient myth in only two decades.
That all alien races can speak speak perfect english, albeit with dodgey accents.
That there would be a whole army of robots more effeminate than C3PO.
That there would be more star wars movies after Jedi.
That as adults they'd still be buying star wars toys
