YOU SAID:

when I was younger, so much younger than today.

INTO JAPANESE

私が若かった頃、今日よりずっと若かった。

BACK INTO ENGLISH

When I was younger, I was much younger than today.

INTO JAPANESE

私が若かったとき、私は今日よりずっと若かった。

BACK INTO ENGLISH

When I was younger, I was much younger than today.