I was just wondering your opinons on somthing. Do you think that its appropriate and valid for high school students to be forced to read a novel from the literary canon even though most students wouldn't be able to understand and comprehend them after only being given a few weeks in order to study the novel.

Yes, I think it is absolutely appropriate. If you don't start learning to read literature at high school, you may never be able to. And no one understands their first difficult novels in one go. Reading takes practise!

And nowadays, you can get so much help with understanding a book from the internet. When I started reading literature, I still had to drag myself to the library and find special books with interpretations! (or even worse, write my own...)

Depends - what's the novel? Ulysses by James Joyce, no. Salinger's Catcher in the Rye, sure. How is one to know that 'most students' wouldn't understand whatever it is, anyway? Assuming a fact not in evidence, innit.

That is not to say I found any particular value in The Great Gatsby myself, even though it is often listed as one of the greatest books written, right.

Yes And No, an answer you will encounter again and again, requiring interpretative skills. Nuff said