http://www.amazon.com/You-Need-Be-Little-Crazy/dp/079318018X...
I'm 39.5 with 3 kids and working at my 3rd startup. You make sacrifices and I'd be lying if I said my marriage hasn't been strained at times mostly due to financial worries.
It really comes down to this:
“If you bring forth what is within you, what is within you will save you. If you do not bring forth what is within you, what is within you will destroy you.”
You have to bring it forth!
Cheers
I think it's this personal transformation that's one of the hardest things about a startup. You start out wanting to change the world and end up at 3AM wondering what's gone wrong and realizing that it's you has to change first.
Barry Moltz wrote a great book "You Have To Be A Little Crazy" that addresses the emotional roller coaster that every entrepreneur faces, observing "Entrepreneurs start businesses because..they have no choice. Passion and energy drive them on good days and sustain them on bad days." Some references follow:
http://www.amazon.com/You-Need-Be-Little-Crazy/dp/079318018X...
http://www.skmurphy.com/blog/2006/12/27/you-need-to-be-a-lit...
My thesis is that most entrepreneurship is involuntary (either due to fundamental personality characteristics or lack of opportunity to do anything else). If you like the structure corporations provide, embrace it. My only caveat is that most have done away with a commitment to lifetime employment, give some thought to what you might do if you were not able to continue to work in a corporation. I think the best book on the psychology of entrepreneurship is "You Have to Be a Little Crazy" by Barry Moltz http://www.amazon.com/You-Need-Be-Little-Crazy/dp/079318018X... who concludes:
"Entrepreneurs start businesses because..they have no choice. Passion and energy drive them on good days and sustain them on bad days."