I was just about to say that

When someone says what I want to say on ahead, I can use this sentece at once.
"Joni Mitchell is not only a musician but also a wonderful painter. She's a kind of genius" "Yeah, I was just about to say that."
There are some ways to say. One of them is "You took the words right out of my mouth". My teacher told us that expression was used by many English speaking people in everyday life. If I could use those expressions well, some people should think that I was a good English speaker.^^;