If you have a job, good, lots of people do not. If you have a job that is decent, great, you are probably somewhere in your life. If you are not doing what you truly are meant to do, there is a problem and we need you to be all you can be.
Bob Parson’s started his website business while holding another job. Does he live his dream? Damned right. Nobody asked you to stop everything you do in order to pursue your 10000 hours. If a failure or an immense challenge, having a temporary back-up plan is exactly like having an insurance plan.
Again, start now. While the world is in turmoil with the occupancy of financial markets (like "predicted" here ), new opportunity to build something great is now turning into reality. The best of us does not come when everything is going well, but when everything seems to be falling apart.