University of Waterloo Admission Information Form Problem?

The AIF is not the only thing they look at. A well written and impressive AIF will increase your chances, but it is not the end of the world if you messed up a little on it. Write the math contests and do well in them. Meet and exceed the "required mark" for admission and if your teacher reference says good things about you, I would say you still have a very good chance. Good luck!