When I was in Seminary, World Religions was a required course. I took it from a missionary on home leave, and he was totally awesome and so were the books we used. Of course, it was from a Christian perspective, but he loved to play devil's advocate, and see what the class of future pastors and missionaries did with it. A lot of times we were totally lost about how to witness to the people from various religions.
We even visited a mosque, which was a very good experience, and helped me reallize Muslims were people, and many of them kind people. Just totally deluded about God! There was one man there, who was the son of the former Moderator of the United Church of Canada (the biggest Protestant denomination in Canada, and totally apostate!). A group of men in our class took him on, and they were very gentle, but he just didn't have the answers and finally ran out of the mosque because he didn't want to hear the truth about Jesus.
I would approach your professor alone, after class, and tell him your dilemma. There is nothing wrong about learning about other religions, especially if it helps you witness to people from other religions.
Plus, I like to think of Christianity as my relationship with God, not my religion. Maybe that will help you get through the class if it is required.