Do our prejudices of the “Bible Belt” in America differ from the present reality in the United States?

When I decided to spend my exchange year in Oklahoma I was not aware of entering a region which is informally called “The Bible Belt”. So shortly before my departure I collected some information about the people I was going to stay with and their customs. I found out about the region’s term “Bible Belt” which is a term for an area of the United States in which socially conservative evangelical Protestantism is a dominant part of the culture and Christian church attendance across the denominations is extremely high.
But if that was just a prejudice or actually a fact I would figure out later during my exchange year by living in the region of the “Bible Belt” myself.
And fact was that my town with about 1500 inhabitants had 7 churches. My host father told me right in the beginning of my stay that he wanted me to go to church with them at least every Sunday. Since I had already decided to adapt my “atheist” lifestyle to a more religious one during this year in order to get to know the people better I was staying with I agreed with him. But I don’t want to know what he would have done if I had said no.
Even in school where religion is supposed not to influence other classes I was astonished when my Biology teacher skipped the chapter in our book which was dealing with the theory of evolution.
The strong influence of Christianity in the region of the Bible Belt is definitely not a prejudice and everybody going there has to be prepared that people try to convert him and convince him that their believe is the true one and all other kinds of religions are “wrong”.