YOU SAID:

This book series is about 18 year olds

INTO JAPANESE

この本のシリーズは約 18 歳です。

BACK INTO ENGLISH

This book series is about 18 years old.

INTO JAPANESE

本シリーズは、約 18 歳です。

BACK INTO ENGLISH

This series is about 18 years old.

INTO JAPANESE

このシリーズは、約 18 歳です。

BACK INTO ENGLISH

This series is about 18 years old.