YOU SAID:

I did not know she was only sixteen.

INTO JAPANESE

彼女は 16 歳だったとは知りませんでした。

BACK INTO ENGLISH

I did not know she was 16 years old.

INTO JAPANESE

彼女は 16 歳だったとは知りませんでした。

BACK INTO ENGLISH

I did not know she was 16 years old.