Would my acceptance be withdrawn?

I was accepted to the University of Toronto for Economics at relatively early stages of the application process. The condition of my acceptance was that I "maintain acceptable final average", or "acceptable final marks in prerequisite subjects". Nowhere do they say what is considered "acceptable". The only problem is that my calculus mark, which is a prerequisite dropped to a 63. is this an unacceptable mark? my final average is still around what it was when i was first accepted. What do you think?