No that's not necessarily the friend zone. She was put on the spot and maybe wasn't sure about you just yet.
I love these "friend" situations, they are so easy to play:
You respond to her and everyone to hear: "haha I'm just messing around with her having fun she is funny as he|| ! But she is not my type either so yeah she is right we are just friends".
Early on NEVER tell anyone around you have interest, even YOUR friends, UNLESS you are 10,000% sure they won't turn around and c0ck block you and make a joke out of it. Play with others' heads too until you seal the deal.
You see, her hearing that you only think of her as friend will make her little hamster brain start going "Just friends? I am only good enough to be his friend!! I am better than that!! " Then she will start chasing you and wa la!