I'm guessing you're not super interested in changing your mind, but here's some actual info for anyone interested.
"The four corners of the earth" is a poetic device. It alludes Old Testament passages like Isaiah 11:12 ("And he shall ... assemble the outcasts of Israel, and gather together the dispersed of Judah from the four corners of the earth.") In context it means something like "the whole world" because it refers to all four cardinal directions. It's like "the four winds". It's the same basic phrase as "to the ends of the earth" that is in common usage even in our day and doesn't literally mean to where the earth ends, it means something like "as far as you like".
The bible elsewhere explicitly states the roundness of the earth and it floating in space in less metaphorical language.
* "It is He [God] who sits above the circle of the earth, ..." - Isaiah 40:22
* "He stretches out the north over empty space; He hangs the earth on nothing." - Job 26:7
* "He drew a circular horizon on the face of the waters, At the boundary of light and darkness." - Job 26:10
The bible is generally unconcerned with things like this, instead emphasizing the *origins* over the structure. Nonetheless, it's still there in incidentally, sometimes.