Fearlessly plunging into the unknown, is indeed the key to success. Success is not only realized in terms of monetary gains, but also in terms of personal growth.
The hardest thing to do is to go out of your comfort zones. However, those who manage to do this, tend to reap great rewards. You gain a sense of satisfaction by doing sometime out of the ordinary.
So go for it. You have an idea, jump upon it. As the well known English saying goes, "strike while the iron is hot." Or rather better put 'seize the opportunity while the idea is hot.'
Seize upon it while the idea is fresh in your mind. That is when you will have the greatest passion and drive. Be ready to go all out and develop your idea, no matter what the consequence.
(Blog post inspired from an email conversation between myself and a dear friend, Moazzam Chaudry)