The first question you must ask yourself is how much you want to be in the Entertainment business. To succeed in any arena of Hollywood you absolutely must want it more than anything else in the world.
This business will beat you to death and you will still want to be in it. It has ruined numerous marriages (including some of mine) and relationships. It has caused people to drink and do drugs. After all, it ain't easy being nice to people you can't stand, but you will have to do it. There will be years when you won't earn a dime, but you will have to keep doing it. Your years on the top of the ladder are finite. The saying goes that the only job that lasts in Hollywood is being an Agent. Everything and I mean everything else throws you out once you make a bad enemy, age out of the system, start relying on your talent or agent or luck to keep you on top.
There are important people in Hollywood that will eat you up and spit you out. They will use you and abuse you. Your agent will stop returning your calls. Your producer will fire you off of your own picture and hire someone else. You will simply grow cold and may never know why.
All this is to say that you really have to want this work more than everything in you life. You must be willing to move to Los Angeles, or New York. You must start before you are 35. You must learn your craft better then anyone else you know. If you are shy you better get over it. If you are always sure that you are right, you better get over it.
By now you are probably depressed as hell. Don't be. Remember it is still the greatest business in the world and there's only a small amount of people who make it big. Maybe you will be that person. Maybe you have the talent, foresight, and determination that it requires.
Hope springs eternal, however I hope you think long and hard about this. Then if you decide to jump in you might make a fabulous splash!