YOU SAID:

Haven’t I already done this before

INTO JAPANESE

私はすでにこれをやったことがありませんか？

BACK INTO ENGLISH

Have I already done this?

INTO JAPANESE

もうやりましたか？

BACK INTO ENGLISH

Have you done it yet?

INTO JAPANESE

もうヤッちゃったかい？

BACK INTO ENGLISH

"Have you done it yet?"

INTO JAPANESE

もうヤッちゃったかい？

BACK INTO ENGLISH

"Have you done it yet?"