As a repeat entrepreneur, I must say the number one thing for me has been my passion for solutions/ideas. It is stressful and comes with its challenges, but staying true to your vision and the main reason you undertake such a jump drives you to a level of success that is extremely rewarding. I had personally invested all I had into my last two ventures and then got help from outside when I proved my idea and ended up with very decent exits to public companies. The knowledge gained wearing ALL the hats in a startup and being able to take an idea to a product and get like-minded people to follow up and even invest in you becomes the most incredible thing you will ever do, no matter at what age. I always tell people, if you ever thought about doing it, do it. You won't regret it.