Many people come to Los Angeles to act, and it always surprises me when I learn that they come expecting to be discovered without any idea of how to audition or how to work as an actor. Although I received a BA in Theater Arts at a UC, I never had any desire to work in the entertainment industry; instead, I used my education and skills in sales where I made money presenting my products to the marketplace.
If you don't want to spend four years and several thousand dollars getting a degree, there are great classes for people who would like some education and preparation for acting, like Acting Organics or The Groundlings School. Both offer professional teachers who actually work in the industry teaching the basics of how to prepare and succeed in a career here that is not based in the fantasy of being discovered simply by drinking a soda at a counter in Hollywood.
Acting is work, and if you want to work as an actor, you must be willing to study, present yourself, and persevere in both your education and in the face of rejection. Classes are a safe and fun place to hone your craft as your prepare for that one part that may change your life. Education is always necessary, no matter what your career or your age, so you might as well do it by choosing to study something you want to do with your life. If you want to be an actor, you will be a better actor if you study the art of acting.
If you only want to to be famous, then just apply to be on a reality show.