I haven't read all the responses to your post so pardon me if I'm repeating what's been said. Or maybe I'm contradicting something that's been said, in which case don't pardon me.
I hope you aren't looking at your 401-k/IRA as part of your cruising kitty. If you're worried about turning 50 now, wait till you've turned 65 and haven't saved anything. Don't touch your retirement savings--add to it regularly, even if it's a small amount. Use a fee-only financial advisor. Not somebody who will buy and sell on your behalf and charge you each time he does it. You get better advice that way, for less money, and come out the same in the end. Be diversified. That means mutual funds, not stocks, if you're on a tight budget. And I could be wrong, but I think I recal that you can transfer a 401-k to an IRA without a penalty. Just don't withdraw it.
I hope you've done some shopping at marine supply places. Small stuff costs a lot, and it adds up fast. Likewise marina dock and storage fees should you happen to need to store it for a season. Don't forget to buy tools. And know how to use them.
Get in shape if you aren't already. Sailing can be work, especially single-handing. Haul an anchor
up by hand, move from the cockpit to the bow and back before the course changes, loosen a rusted fastenner. Get thin, flexible and reasonably strong. Lots of perfectly good sailors aren't, I know, but I'd bet most of them have bigger budgets than you.
Be mindful of the living space you end up with, and of how tolerant you are for 'camping' vs just living in a tiny house. The more room you have, the fewer things you have to move every time you want to find something, and the fewer times you whack your head or elbow in the process.