Because of ageism, most experienced professionals start their own businesses, so you are not alone.

I would first take a break and do some soul searching, what do you really want from a career and life in the next 10-20 years. Then, I would to SWOT on your self and the business model and industry that you want to enter to figure out if your goal is worthwhile.

Most businesses will not generate revenue in 12 months. It's great that you have 12 months of living expenses covered, but most likely you will not be able to replace your salary in that time because growing a new business in incredibly hard as internet has globalized competition.

For experienced professionals, the quickest path to revenue is consulting within their industry, contract work with former competitors.

If you like operations, logistics and execution, i.e. are not big fan of unproven new products and innovation, franchising is a good option for you. Getting a franchise will take you about 6 months. If you are buying an existing location, you will start generating revenue from day one, but it will still take you some time to break even. I would do my own research about financial potentials for different franchises; there are some bad apples out there (UPS comes to mind).

Finally, if you want to start you own business, write a business plan first before you pour money into it. Writing a business plan will help you evaluate the financial potential of your idea and force you to put down on paper information about competition, your own competitive advantage, hiring needs, business model, etc. This is my specialty: http://www.anagard.com/services/BusinessPlans.html What I like about writing a business plan is that you are not going into a new business led by passion, but logic. It takes few months to write a business plan document, but it doesn't have to be perfect, unless you are planning to raise money from angel investors. Bank will not give you a loan without few years of revenues to show for. The core of any business plan is a market research: http://www.anagard.com/services/MarketResearch.html

Good luck and call me if you want me to work with you as you navigate uncharted waters.