Hi ... good question.
A career in business is interesting and one of the reasons I have spent almost 20 years in business. It can be very entry level (working at a local store) or you can go to school for up to 6 years for a Masters degree. It depends on what you want to do in the business field...you can do everything from customer service/dealing with customers, sales, accounting, human resources, training people, managing people, managing projects, working with computers..and many more business careers.
I would suggest researching more specific business careers and college programs online to figure out what you are interested in then decide if you want to go right to work in an entry level job, go to community college for 2 years for an Associates degree or a college/university for 4-6 years for a Bachelors or Master degree.