YOU SAID:
I'm going to sleep at nine in the afternoon
INTO JAPANESE
私は午後9時に寝るつもりです
BACK INTO ENGLISH
I am going to go to bed at 9 PM
INTO JAPANESE
私は午後9時に寝るつもりです
BACK INTO ENGLISH
I am going to go to bed at 9 PM
That didn't even make that much sense in English.