I agree with your mom, knowing computers would be a great minor, but only if you want to work in the IT end of business. All large corporations and most smaller ones use computers, so they need people who can tailor the software to the company's workflow needs (business analysts or process analysts), and install, configure, test, and maintain it (not just techies, but often people who know the business side as well as the computer side).
What end of business do you like? Marketing, finance, accounting, sales, management, entrepreneurship, operations, HR (Human Resources, hiring and employee benefits), product design?
What industries interest you? Banking/investing, healthcare, retail, fashion, food, entertainment, sports, education, advertising, social services, construction, what?
You don't really need to decide at this point, just explore what's out there. Once you're in college, you'll take some basic business courses in all different areas, and that can help you figure out what attracts you. For now, explore by reading magazines such as Business Week, Forbes, Fortune and Fast Company. You don't need to memorize every article, just see what's there and read what interests you. When you find yourself gravtitating to the same kinds of articles over time, those will be things you might want to pursue.
Realize that many people just want to be in business and are open as to the actual industry or type of job they have. They may find positions they'd never considered. Examples: Supply-chain management, insurance underwriting, implementation consultant, public relations.
Answered By: MavistheMaven - 3/12/2011