It's odd that you have a Schengen Visa - Canadian citizens do not require a visa to enter the Schengen Zone!
Icelandic laws state that your parents are responsible for you until you reach the age of 18. I am not sure if you need a letter of authorization but i would not be surprised if you did.
If you can get the letter you should do it. Otherwise we might mistake you for a runaway and then our child protective services and foreign office would have to intervene.
I have been travelling alone since I was 15. Most of the idiots here say 18 is the min. They are talking crap
Yes,
just to be prepared, have a letter from your parent(s) with you authorizing you to travel alone. Invest about 2 minutes of your valuable time to write it.