You do *not* have to believe in Darwin's theory of evolution. You don't have to believe that it explains the creation of the universe, or us.
You do, however, as a student, and a citizen of the world, have to understand how the theory works, and how it explains how life evolves *now* -- which is why we can't use last year's flu vaccine this year, because viruses evolve. Because life evolves.
Darwin's theory is not a replacement of Genesis 1 or 2. It explains how life works now. It has ZERO to do with how we got here in the first place. You can believe that it explains how life got here, using Darwin -- or you can not believe it. That's what freedom of belief in the U.S.A. affords us all. But you still have to learn that evolution works and how it works, and that is why we have to learn it in science classes.