It was about some kids on a space station. Their society had created myths about their creation that were centered around the space station being the whole world and the kids find out the truth. I know it was included in a 7th grade reading text called Moments in Literature. It's been bugging me for 20 years. Can anyone help?

Could it be "The Sense of Wonder," by Milton Lesser?

...and if not the Lesser story, it could be one of many other works, since the "whole world turning out to be just a space ship" is a common device in science fiction. The classics of the genre are UNIVERSE by Robert Heinlein, NON-STOP by Brian Aldiss, and many others. (The two I have named are novels, by the way, not short stories.)