What is the difference between ένα and μία? They both seem to be feminine.
The former is neuter and so is κορίτσι.
(το) κορίτσι is grammatically neuter gender, although a girl is a female. It is a Greek irregularity!
Ahh, I see, like "das Mädchen" in German. Ευχαριστώ :)
Yes, very much like that. The same seems to apply to the Greek for boy, which also appears to be neuter (to agori).
It's the general tendency for words for children to be neuter, e.g. das Kind.