YOU SAID:
I'm out with the girls
INTO JAPANESE
私は女の子と出かけています
BACK INTO ENGLISH
I am going out with a girl
INTO JAPANESE
私は女の子と出かける
BACK INTO ENGLISH
I go out with girls
INTO JAPANESE
私は女の子と出かける
BACK INTO ENGLISH
I go out with girls
That didn't even make that much sense in English.