I'm impressed you're thinking about this! Here are three courses I'd definitely recommend:
- Micro & Macro Economics - for foundational business concepts
- English - being able to clearly communicate (in person and in writing) is an extremely important skill in business
- Statistics (or prerequisite math classes to be able to take statistics) for non-majors - understanding probability and statistics is arguably the only math class you'll use after college.
- Bonus: Political Science - will help you understand the ways that international and domestic politics impact businesses
It really depends on what type of job you'd like in business - you can go a few different directions like marketing, operations, finance, sales, etc. - but all the courses (or topics) above are broadly useful for anywhere you want to go next. I've been in marketing for 7 years now, and I use these skills every day.
The other advice I'd give you is to get a job in an office environment, so you can get familiar with office dynamics, learn how to navigate a business environment, build organization skills, and learn more about what types of work you do and don't like.
Good luck and have fun!