I'm 18 years old and I want to start investing, where do I begin?

I'm 18 years old and have little money, where should I start investing? Is it better to invest in myself and financial education first? Should I open an account with a brokerage firm that doesn't have fees? Are fixed-income investments like Treasury Direct, CDBs, and funds a good start? How can I avoid promises of quick money and think long-term?