YOU SAID:
I hope it was her kid ;)
INTO JAPANESE
;) 彼女の子供だったと思います
BACK INTO ENGLISH
;) I was the child of her
INTO JAPANESE
;)私は彼女の子供だった
BACK INTO ENGLISH
;) I was her child
INTO JAPANESE
;)私は彼女の子供だった
BACK INTO ENGLISH
;) I was her child
That didn't even make that much sense in English.