YOU SAID:

katie was a boy but is now a girl

INTO JAPANESE

ケイティは男の子でしたが、今は女の子です

BACK INTO ENGLISH

Katie used to be a boy, but now she's a girl

INTO JAPANESE

ケイティは男の子だったけど、今は女の子

BACK INTO ENGLISH

Katie used to be a boy, but now she's a girl