There is no fooling a child. I was raised in a home of an alcoholic. Maybe, I didn't know the word "Alcohol" I knew something was very wrong. No one ever explained it to me, and, to this day, I think that it was wrong, it took me along time to work through their little secret.
Personally, I think that you have opened the door, and, when she is ready she will ask you questions, and, to me, this is good.
Just my two cents.