Jessica, there is a product called Z-Brick and by perhaps other trade names that is just a thin brick face with grout. This is made to be glued in panels onto the walls. If this is what you have, go ahead and paint it. The stuff is almost impossible to remove from the walls without doing major damage to your drywall. Unless you have a real desire to replace drywall, you can paint as you wish but do go to a paint store and get a product that is made for this. I don't know how to tell you an easy way to tell if it is this product except that you should be able to find the real joint lines where the panels interlock.