YOU SAID:

i turned eightteen today

INTO JAPANESE

私は今日１ ８歳になった

BACK INTO ENGLISH

I turned 18 today.

INTO JAPANESE

今日18歳になった。

BACK INTO ENGLISH

Today I am 18 years old.

INTO JAPANESE

年齢は１８歳です。

BACK INTO ENGLISH

I am eighteen years old.

INTO JAPANESE

年齢は１８歳です。

BACK INTO ENGLISH

I am eighteen years old.