Didn't major in business? No problem.
I majored in English as an undergrad ...well, initially I majored in English, then switched to Cinema and Photography, then switched back to English in junior year when I transferred from Ithaca College to Ohio State. (In 1996, Ithaca had eliminated the BS in Film Studies major to focus on the BFA in Film Production, which did not interest me.) To sum it up, I never took a single business class as an undergrad. I took an honors math course my freshman year and at Ohio State I took Statistics, but that's about all that I could apply directly to MBA knowledge. I can tell you all about Shakespeare and film history, though.
I worried a little about how I'd do in the MBA program, that I'd be behind all of the other students and totally clueless. I wasn't worried about my math skills, but my business knowledge. Kind of like Harry Potter going off to Hogwarts for the first time, worrying that growing up in the Muggle world instead of the wizarding one would put him at a disadvantage. I didn't need to worry. We all have our specialties in the business world. I'm in class with engineers, doctors, and fellow humanities majors who also likely never stepped foot into a business class or read a case before. That's what makes class discussion so interesting. The varying business worlds we inhabit help inform our studies and add to the conversations we have together.