Take the classes you need to find a job doing what you want, then use that job to learn what you need to know to start your own business. There are a lot of resources on how to start a company, but knowing what niche to pick is harder to come by. A stable job where someone else worries about payroll and corporate tax strategies is a good safe harbor until you're ready to make the leap.

Also consider that sometimes hobbies are fun because they're just that: hobbies. You should have passion for your work but finding something fun is not always a good indicator that you'll enjoy it 40+ hours a week or be happy depending on it for your livelihood. For example I really like teaching but am I okay with long hours and poor compensation? Not likely, at least at this age (34).

Good luck!