YOU SAID:

Do you have another sister because I do, a younger one.

INTO JAPANESE

私の妹は若いので、別の妹がいますか？

BACK INTO ENGLISH

My sister is young, do you have another sister?

INTO JAPANESE

私の妹は若いですが、別の妹がいますか？

BACK INTO ENGLISH

My sister is young, do you have another sister?