Something super simple and revealing is try pressing on the brakes with your left foot.

That's because after you've learned to drive, everything the feet do is muscle memory. You don't consciously adjust the pressure (you just believe you do..), so switching around the pedals will need re-learning. And indeed it's common among rally cross drivers to learn to use the left foot with the brake pedal as well.

A few of my relatives who grew up on a farm drives that way (right for gas, left for brakes)