Here you are a proud owner of a high school degree. Or maybe you dropped out last year.
If you are one of the few that KNOWS what they want to do. Do it!
If you have a dozen people telling you what to do, and don't care yourself; start a business.
Take the thing you are most passionate about, then figure out how to make money at it. Start the business, then find and ingest all the knowledge available about that subject.
The best way to learn about business is not by going to school, it is by starting a business, and trying to make it profitable.
An exception might be if your passion is something like clothing. Get a job with a rags merchant, then work hard and get into management. In a couple of years you will understand the business, how to drive a profit and loss statement, and how to gauge demand.
Then start your own business.
If you are still in school, at any level, start your business on the web. There is less regulation, there are less tax problems, it is less expensive to start; and easier to start again if the first efforts fail. Keep trying.
At BFU we have a great deal of free learning resources you can use to help you get started. At Silent Partner we have more educational materials available, like this article on financial freedom. Use this free information to keep your start up costs low.
If you want to start fast, spend a small amount of money and get some good software, such as this for a home or small business.
If you already have a web presence, check the power of your site here. Now figure out how to make all that traffic you built pay. As we academics say; monetize it.
Do it for yourself.
Do it now!