[jcr]

Live very simply for a few years while working as a doctor, learning in your free time, and building up a bankroll of funds. If you find that you don't have the motivation to learn, fail, and pivot in your free time, then you probably won't have the motivation to do it full time.

Edit: You could replace 'motivation' with 'ambition' if that reads better to you personally, but they are nearly the same.

[jcr]

Also, you could probably learn a lot from Patric (HN user: patio11) about the process of building your own startup while remaining employed. You'll find his blog posts very useful, particularly the way he thinks about identifying problems, and how to solve them.

http://news.ycombinator.com/user?id=patio11

http://www.kalzumeus.com