Wonderful news! Attending your first Liturgy is never as scary as you imagine. I didn't realize it was an all Greek Liturgy. While it sounds holy and mysterious, if you don't understand Greek, will that be a frustrating problem for you eventually? I imagine it's the same problem as an all Latin mass.
It wasn't all Greek - some of it was in Greek and some was in English. Which isn't hugely different from our old Byzantine Catholic parish where some of the Divine Liturgy was done in Ukrainian (which I don't speak either). Eventually we just got used to the phonetics (if not the meaning) and we knew what was happening even if we didn't truly understand the language. Which is not unlike the Latin Masses we have attended. Though I admit that following along with the Latin was easier as we share a common alphabet and many of the words are obvious as the root of the English words. The Greek is a bit harder to "dope out" as the alphabet is so considerably different.
I assume it will be somewhat the same here that we will easily understand the English portions and learn the meaning, if not understanding the language, of the Greek portions.