YOU SAID:
My mom left when i was 7
INTO JAPANESE
母は私が7歳の時に家を出た
BACK INTO ENGLISH
My mother left home when I was 7 years old
INTO JAPANESE
母は私が7歳の時に家を出ました
BACK INTO ENGLISH
My mother left home when I was 7 years old
That didn't even make that much sense in English.