YOU SAID:
They were babies when I last saw them.
INTO JAPANESE
最後に会った時は赤ちゃんだった
BACK INTO ENGLISH
The last time I saw her, she was a baby.
INTO JAPANESE
最後に彼女に会った時彼女は赤ちゃんだった
BACK INTO ENGLISH
The last time I saw her, she was a baby.
That didn't even make that much sense in English.