I participated in that other thread that CCL referenced earlier - as to why you may care about my opinion - I worked for the admissions office of a major Canadian medical school a few years ago - I’ve since changed positions within the Faculty, but I still offer student advice on occasion.
Sooo - that being said. Our medical school will accept people with only two years of college under their belt, but the preference is a degree - I’m unclear if you have a degree, or a pre-med type diploma.
Our school has accepted more than one 19 year old student - I have to say - those students were REMARKABLE. Not only fabulous grades and stellar MCAT scores, but really all round amazing people. Concert pianists that could speak 5 languages and had been volunteering with child burn victems since they were 10 (the candidates, that is). I’m serious - and I may be exagerating a little, but only a very little.
This year, you will probably not be accepted. However, at my school that wont prejudice your chances in future years. If you feel like this is something you really must do now, go for it, but be prepaired for dissapointment - this year anyway.
Get yerself a back-up plan. Admissions committees like to see people that are doing more than just applying to medical school - if you don’t have any job experience, get some. If you don’t have any volunteer experience, get some of that too. Research experience will help your chances also.
Regarding the MCAT - you can write it 3 times before you have to start justifying why. Your scores will be valid for 6 years from writing date. If you get super scores, they should do you until you get it. If you do choose to re-write it, most schools will only accept results from one complete exam - that is, they won’t cherry pick for the best scores from different tests.
Let me wrap this up by repeating what I said earlier - at most schools a previously unsuccessful application will not negatively impact a future application. Assuming that you’ve done something productive with the year in between applications you should be fine if you apply now, and then apply again if unsuccessful.
Good luck - it’s rare that people so young are so sure about their future career path. 