Good luck with the plans.
I've read through all the replies, and every one is good advice, as you said a great bunch on here.
I went self employed many years ago, and now on my third business, as the economy ruined the others (being luxury services) so my advice is go for it, once you go self employed you'll wonder why you never did it before.
Earning your own income, and the excitement of building a business gives you a drive and self confidence that you never had before. If anyone asks, you own a window cleaning business, be proud of it, nothing wrong with cleaning windows, but be prepared for the ones that look down on you, just build a thick skin...
You'll also change your mindset like most entrepreneurs do, because you're constantly thinking about business you'll notice other opportunities and the like.