Go for a part-time or executive MBA program - it'll be a better fit for you. You will be in an environment with people who are at a similar stage in their life/careers (and by extension - age). And you'll likely have a better shot at these schools too.
If you're looking to start a business, the last thing you should be doing honestly is to spend $100K+ in tuition on an MBA program full-time. Better off financially by working the day job to help minimize the cost of attending.
A lot of businesses fail because of lack of knowledge. But even more business don't even get started in the first place because of a lack of guts and heart. And the "knowledge" part can't be taken care of in an MBA program -- it comes from actually diving in and doing it, and learning how to adjust on the fly.
If you have a compelling business idea, start it NOW. There's always way more excuses not to start it (i.e. get an MBA, oh sell my house first, oh then maybe work a few more years to build up capital, oh maybe wait until my kids are in college, and so forth).