The only limits are the ones you put on yourself. Said another way...you can do anything you want to do. It's not going to be easy. It will take work, often a lot of work, but if you put in the time and energy, you can accomplish anything.
Stop listening to the naysayers. Pay no heed to the soul suckers. Forget about the doubters. Ignore everyone around you who doesn't support you. Believe in yourself, especially when others don't. Rise above the day to day bullshit and follow the path you want to follow.
No matter what you do, there are always going to be people who think you are crazy; people who will tell you no; people who will doubt you; people who just don't understand you. If they are going to be there no matter what, shouldn't you focus on what you want to do? Find people who will support you and surround yourself with them, then hit the ground running. What do you really want to do? What's really stopping you?