Don't forget to get a passport! It can take a good while. And they often reject the first application because of some trivial photo reason, like the background being a shade of white they don't like! This is a good thing to get done well, well in advance !

I went to Crete in August, I'd say you don't need to learn Greek as people are used to working with tourists, but if you're thinking of going to the islands I'd recommend flying there rather than taking the ferry. For me, Crete has everything from world famous beaches (Balos, Elafonisi, Seitan, Preveli, Vai), history (Knossos, Phaestos), graphic towns (Chania, Rethymno), nature (Samaria gorge) and as for food they usually get you big portions. However I'll warn you: Greece, for how small it is, it takes hours to travel from one place to another and the roads are kinda scary. I ended up going only to half of the places I wanted to see, so don't make too many plans. Oh and be aware of the wildfires.

Okay, first thing's first: https://media.istockphoto.com/id/1406490064/vector/comparison-of-greek-latin-and-cyrillic-alphabets.jpg?s=612x612&w=0&k=20&c=Vnpyim7uYy1wiPer2HJbIA_-G2_Eo4RYeXjL6I_z4IM= Save this image. It's the overlap between the Greek, Roman, and Cyrillic alphabets. You're probably thinking "That's an interesting bit of trivia, but there's no way that information would ever prove useful in my life". Everyone thinks that; everyone is wrong. At some point, it WILL come up, and you WILL be slightly inconvenienced if you don't have quick access to it. Get out ahead of the problem, and you'll eventually be glad you did.

That said: nice! Be sure your passport's current, and if not, fix that; it can take a while, so do it as soon as possible. You might want to look at getting a cheap backup camera, in case something happens to the first, just in case.

I've never been to Greece, but two important things:
1. the people there are probably familiar with saganaki, so ordering it for someone else's table will produce much less comical reactions, and
2. don't laugh at the evzones. Yes, their uniforms are predicated on the idea that it's hard to fight an enemy when you're laughing uncontrollably, but they're still well-trained, elite soldiers.

Have fun!