Unless you are using a 'directional' fabric (stripes, figures that would be standing on their heads, velvet, etc) this should not be a problem. Usually in a quilt you have pieces small enough that it is not an issue except for borders.
I remember years ago trying to help a friend make her first garment. She had chosen a fairly simple pattern, but her fabric was directional with fairies sitting on mushrooms. Fortunately we discovered that they were all facing the same way before cutting the main pieces upside down. She did not want to unpin everything and turn it around but eventually wisely decided that was better than wearing it upside down.
Again, this should not be an issue with your quilt block, but thought you might enjoy the story.