You are the first person I have heard define Midwest that way. Midwest includes Ohio, Indiana, Michigan, Illinois, Missouri too [1]. Although many people view the Northwest Territory [2] after the revolutionary war as the "Midwest": Ohio, Indiana, Illinois, Michigan, Wisconsin, Minnesota. Culturally, the second definition makes more sense to me as someone who has lived in Ohio, Indiana, Illinois, and spent significant time in several of the other states in the first definition.

1. https://en.wikipedia.org/wiki/Midwestern_United_States

2. https://en.wikipedia.org/wiki/Northwest_Territory