For a smooth game experience, everyone should understand what the game is about. Basic rule of roleplaying.
We have suggested the opposite before: keeping details of the setting secret and deliberately building up false player expectations, in order to throw a surprise twist. We said it then, and we repeat it now: Only try that if you know your players very well.
If you're still feeling your way, or running your first adventure, keep things straightforward. You can save your apologies for more important things.
R2-D2: Hey everyone. Annie not here yet?
Padmé: She should be here soon.
R2-D2: Sally, I brought you a present. Here.
Yoda: A book? The Prince?
R2-D2: It's a classic treatise on how to be an effective politician. It'll be great for your career.
Yoda: I don't want to be a politician any more. They're all self-serving and evil!
R2-D2: Whatever gave you that idea?
Obi-Wan: She lost the vote for class captain.
Yoda: I'm going to be a vet!
Anakin: Hi! Ah good, you're all here. Before we start, I owe you all an apology.
R2-D2: What, even me?
Anakin: I had this great... well, what I thought was great... high concept for a game setting.
Anakin: But didn't explain what it was, and expected you to just go along with it. So, I'm sorry. I'll do better next time.
R2-D2: But it was awesome. I had the most powerful character ever!
Obi-Wan: Well there's your first clue that it didn't go as planned.