Do you have a Certificate of Canadian Citizenship? In our experience this took quite a while (~9 months). However, when you write “…and made sure I had a Canadian citizenship when I was born”, this sound like exactly what your mother probably already got you.
Assuming that you already have this, you need to get your applications in. The deadline for applying to many Canadian and American universities has already passed. One option of course is to take a gap year and apply next year. I have also heard that there are a few universities for which the deadline has not yet passed (Waterloo, Trent, Dalhousie, Acadia – all very good universities). I don’t know about Ryerson.
Before showing up to attend university in Canada you need to to get a Canadian passport. However, with the certificate of Canadian Citizenship already in hand the passport only takes about two weeks or so. Note that the photo requirements for Canadian passports is different from American passports. Thus you either need to find a photo shop in the US who know the Canadian requirements, or go into pretty much any photographers shop or drug store in Canada and get the photo done there. When you send in your passport application you will also need to send in your Certificate of Canadian Citizenship. Keep a copy because you might need it for a step below. They will return it about the same time as your passport shows up.
You will need to get a social insurance card. This is the Canadian equivalent of a social security card. I am told that this takes about 15 minutes at any services Canada location. There are a lot of these all across Canada. We were supposed to do this a few weeks ago for my daughter (who will start university in Canada in September), but due to one of the recent snow storms weren’t able to do it on our last trip so I don’t actually have experience with this step. You will need to take both your Canadian passport and your original Certificate of Canadian Citizenship with you when you get this.
Yes you pay the Canadian price. There is a special deal at McGill for “Canadians born abroad” who pay the same rate as residents of Quebec, which is actually less than the rate for other Canadians. However, when applying you send the same information that they expect from Americans, such as SAT scores for most large universities (not needed at Acadia and some other small universities). You will need to fax or scan and email a copy of your certificate of Canadian Citizenship to the university in Canada that you attend.
Your US high school will need to send your transcript to whatever universities you apply to, regardless of whether they are in the US or in Canada. Ditto for SAT (sending to a Canadian university is the same as to a US university – each university has a code which tells the SAT where to send your scores). No translation needed (most Canadians can speak American well enough ;-).
My daughter is just hearing back from universities in Canada (applications were in a month or two ago), and is getting financial aid offers. The first one that we got was better than I expected. However, you are probably past the deadline for applying for this year if you want financial aid. If you take a gap year and if you have sufficient grades then financial aid from the university is possible. Without any aid, Canadian citizens attending Canadian universities are nearly always paying less, sometimes much less, than American citizens with the same grades attending academically comparable US universities.
You can use funds from a US 529 plan for Canadian universities. I have no idea about loans.
There are many good reasons for Dual citizens who live in the US to attend university in Canada. Best wishes!