You are asking some questions that NO ONE in the world can answer until those things happen. Many, tons, infinite number of highschoolers have the SAME questions in mind but will never find out the answers until the future comes.
I know many friends who go to UBC and Queen's. Many excel. Honestly, I personally know 5 people who graduated with GPA in the range of 3.95-4.0 (90%+ average) and many more with 3.7+ GPA. And the ones with near 4.0 GPA have gotten into Univ. of Pennsylvania, Yale, Vanderbilt, Wash U, etc. for med schools. But many other kids go to UBC also flunk out (a good proportion after that infamous first year.) but many of these kids probably went to highschools that had very easy grading (there is no SAT in Canada to standard and compare the performance of highschool graduates).
Similarly, 90% of the kids go to Ivy league schools are ranked in the top 10% of their highschools. They don't initially go to Columbia, Yale or Princeton (or substitute NYU or UCLA here) for their undergrad and shell out $30k a year to "end up in" state med schools later; they damn want harvard, hopkins, stanford med (well, I exaggerate their mentality a bit to make my point clear)! In the end, however, only a few make it. These people just CREAM their competition @ their highly touted Ivy league schools and graduate with 3.9 + summa or magna cum laude and go on to top 10 med schools. Many more kids graduate with decent GPA's and, by now with more realistic view of things, happily go to their state or other less-reputable private med schools that also provide first-rate medical education (all US med schools are excellent!). However, a few falter and have a GPA of <3.2 and have to fight just to have a med school to go to.
So where do you fall in terms of the above scenarios. NOBODY knows. NOBODY has the vision to see the future for you or anybody else. Just like many of your past, present and future highschool graduates (me included when I graduated from highschool in the mid-1990), you just HAVE TO GO WITH YOUR GUTS. This isn't and cannot be rocket-science. You choose a school that you are comfortable with based on: happiness, money (Canadian schools win out on this), location and reputation (notice I put reputation last). And when you are there, MAKE THE MOST OUT OF YOUR EXPERIENCE THERE. You already know what your ultimate goal is (i.e. med school) so you SHOULD be willing to work hard for it. High GPA will not be handed to you. If you don't get a good start in college (have a GPA of <3.5), then you just have to work harder. By then, it would have been useless to second guess whether you should have gone to U of Alberta instead of NYU (or vise versa!).
So say, you go to U of Alberta and god-forbid, you suck over there. Your GPA plummets to 3.1 and your med school dream is going down the toilet. Does it necessarily mean that if you had gone to NYU, you could have gotten higher GPA? No. If you are semi-intelligent and are willing to study hard, you will probably do well no matter where you go.
The truth about college is that it is a TOTALLY different ball game from highschool. Some people don't do well in highschool but when they get to college, they hit all cylinders and excel, leaving others behind. On the other hand, some people do very well in highschool but falter in college (case in point, somebody @ the Ivy have to get <3.0 GPA even though everybody there was top in his or her respective highschool). Unfortunately, no one can tell you how you will do beforehand. Definitely, some intelligence would make your college career a lot easier than other people have. But who is to judge how intelligent you really are? Even SAT scores don't correlate perfectly with how well you perform in college. And who can tell how hard you are willing to study in college???
okay, enough on this topic
