YOU SAID:

since when did you care about me?

INTO JAPANESE

いつから気になったの？

BACK INTO ENGLISH

Since when did you become interested?

INTO JAPANESE

いつから興味を持ちましたか？

BACK INTO ENGLISH

When did you become interested?

INTO JAPANESE

興味を持ったのはいつですか？

BACK INTO ENGLISH

When did you become interested?