YOU SAID:

I will be 18 years old in a week's time.

INTO JAPANESE

私は一週間の時間で18歳になります。

BACK INTO ENGLISH

I will be 18 years old in a week of time.

INTO JAPANESE

私は、時間の週に18歳になります。

BACK INTO ENGLISH

I will be the 18-year-old to the time of the week.

INTO JAPANESE

私は週の時に18歳になります。

BACK INTO ENGLISH

I will be 18 years of age at the time of the week.

INTO JAPANESE

私は週の時点で18歳になります。

BACK INTO ENGLISH

I will be 18 years old at the time of the week.

INTO JAPANESE

私は週の時点で18歳になります。

BACK INTO ENGLISH

I will be 18 years old at the time of the week.