YOU SAID:

I am too young for that stuff.

INTO JAPANESE

私はその原料の若すぎます。

BACK INTO ENGLISH

I was too young for that stuff.

INTO JAPANESE

その原料のあまりにも若かった。

BACK INTO ENGLISH

That stuff too young.

INTO JAPANESE

若すぎるもの。

BACK INTO ENGLISH

Those too young.

INTO JAPANESE

それらも若い。

BACK INTO ENGLISH

Those too young.