Apparently I'm going to be the only negative voice on this one...
I don't believe in tearing people down just for the sake of it, but in order for me to agree that applying to Harvard is worth your while you're going to have to tell me why you think Harvard would want you. Is there something special or unique about you? Your GPA is 3.50. That's a fine GPA, but Harvard's average GPA is 3.87. As the GPA is the only piece of information you gave us I think it would be ludicrous to give an encouraging response, as yours is significantly below their average. Now it is an average, and clearly they accept people below 3.87 - but presumably these people must have had 'compensating' factors in their app. I'm sure there are other 'qualities' to your application. What are they?
If you are unique in some way, have some distinguishing experiences, publications or whatever then yes, go for it.
If on the other hand you are a cookie cutter pre-med (bio major, straight from undergrad, volunteered in the local ER...., etc) then my perception would be that you would be wasting your money. (I could be wrong but I do not think being Canadian is sufficiently 'unique' - which is the only other thing about you I could glean from your original post).
Of course there is one exception to that - and that is if you wouldn't forgive yourself if you didn't try, and would always wonder 'what if...", in which case I would say 'go for it' regardless of your chances. However, thats more a reflection of my own life philosophy than sound strategic advice.
