Did i say something wrong?

so me and a girl are really good friends (im her best friend) and i like her. We were texting today and she told me she liked a guy that i could tell she liked, i asked her why she liked him (he has a girl friend, and is a ) and she said "hes more mature than anyone else at our lunch (we have lunch with him) he's cute and nice" so i told her the truth i said "hes the most immature out of all of us, and hes a complete to anyone buy you" she said "you dont have to get worried, he has a girlfriend and im not gonna tell him i like him" so i told her i wasnt worried just trying to let her know who he really was. After that she seemed to get pissy and didnt text me back, was it wrong of me to tell her about him??