I’d wait until the light comes on again, and then go fill it up right way. Then compare the gallons filled with the usable gas tank volume from your owner’s manual. This is just a hunch, but I’d bet the light is coming on when it is supposed to. I say this because my 03GP gas gauge was less than linear.

Oh, and 3x on keeping the gas tank on the high side. Keeping the tank fuller will protect the fuel pump from over heating, and it will minimize fuel tank rusting.