I'm 30 and am in an identical decision - except, a few weeks ago, I made the decision to resign from a well paid job at a startup.
A close friend of mine from university are going it alone for the next 18 / 24 months.
I'll be relying solely on my wife's income and our substantial savings over the
next 12 months.
The main propellant that started me on my journey has been the unequivocal support I've received from both my wife and parents (my own and my in-laws).
Once I was clear in what I wanted to do & had a rough plan for how I could achieve those, I waited a few months - thought about the various scenarios day & night and once I had convinced myself it was a risk worth take - I took it to my best friend (and tried convincing him).
Luckily, we have been coding together since university and we decided we could take the plunge together since our temperment and personalities are matched well.
One of my current colleagues encouraged me & said to me it'll be the best experience of my life, to paraphrase his words... "the worst that could happen is that I'd have to
go back to working for someone else. There's no chance that I could die, so why the hell not give it a try?".
When I mustered up the courage to tell my CIO (who I report to...) that I was leaving - he was sad to see me leave, but overjoyed that I'd be taking the risk and trying a new venture (he co-founded the company I currently work for and previously sold an earlier startup to Cisco).
So with the encouragement of others around me, I could only blame myself for not following through and giving the 'startup' thing a try.
... and thus, I would impart this advice to you.
Over the last few months, we've been brushing up our coding skills by building prototypes of ideas we like (and launching them - this is the hard part). One of them is a project we call Math Brain (http://mathbrain.com.au/exam) which helps students in Grade 12 practise for their university entrance exams (or as we call them in Australia - High School Certificate).
The site is not supposed to be a billion dollar business - but it seems to have started getting some regular usage (we were plesantly surprised). Hopefully, we can continue building upon this and perhaps build a proper business out of it (we would never had known if we had never launched it).
At the same time, we're not putting all our eggs in one basket - like you, we've got a number of other app ideas we'd like to prototype and release - all built & following the lean startup methodology.
The difference though, is that we have external pressure to deliver - i.e. both my wife and parents are invested our venture succeeding and therefore we demo things to them regularly. They got sick of me telling them about the ideas I have and showing them mockups of products - now they tell me to shut up and build it.
The trick, I believe is to make sure that you have someone outside of you and your co-founders putting the pressure on to deliver the project. Once you've got this external pressure, your likelihood of success is already higher.
The fact that you have a wife that can support you financially is great - because now you are both invested in making sure you are successful - this is great motivation!!!
I hope this helps in getting the fire started... god speed!