Congrats on your acceptance to Toronto!
I am definitely no expert since I am just now finishing my BA and entering into an MA (potentially at Toronto!), but from what I understand the Centre for Medieval Studies still has a very strong reputation in the US. I am not sure if it is the same for literature, but if you look at the medieval history faculty of some top US programs many of them got their PhDs from Toronto, which I take as a good sign. Although having a degree from an Ivy League school in the US certainly helps your chances of landing a job, they are far from the only schools that place people. Personally I feel that Toronto is still prestigious enough to allow you to have good job prospects in the future.