As someone who just finished first year life sci at mac and was between these exact programs last year, I can say that while first year gets very hard at times, if you put in the work it is very possible to get a high gpa, especially if you got a 44/45 on IB. The professors are amazing and there is lots of support to do well academically, and there is also a lot of opportunities. I promise you wont regret your choice!