Let's see. She's exchange student from Turkey, has boyfriend of course cause good looking and not stupid chick. She's in Athens and she seems to fancy you (no offense, but that means other Athenians are poor male specimen). You kissed her, she likes it. Obviously into adventure. But afraid of it. Chances are you'll get what you want and that is short adventure with exchange student after which she'll go back to Turkey. If you're true alpha that won't bother you the slightest but chances are you're emotional wussy and she could break your heart in the end.
There's also chance she's calling you to have coffee to tell you to piss off in nicest possible way and that she's not interested into advancing your thing further. But think chances for that to happen are considerably lower than alternative.