YOU SAID:
Luna and Harry turn two years old tomorrow.
INTO JAPANESE
ルナとハリーは明日2歳になります。
BACK INTO ENGLISH
Luna and Harry will be two tomorrow.
INTO JAPANESE
ルナとハリーは明日二人になるでしょう。
BACK INTO ENGLISH
Luna and Harry will be two tomorrow.
That didn't even make that much sense in English.