You will need to find out what your budget is. Then you should see whether the schools that you are applying to will fit the budget. This is likely to involve having your parents run the NPCs on the schools in the US.
I am wondering whether or not McGill will fit your budget. It is not as cheap as it used to be for international students. If you have Canadian citizenship, or French citizenship, then this could significantly reduce the cost but I am assuming the answer is no.
Another question might be: what makes you think of applying to McGill? There are a few other universities in Canada that might also be possibilities, some of which cost less than McGill for an international student.
I think that your ECs are fine. I would however think of Wellesley College and Barnard as reaches.