MBA Programs give structured support
Business School: If you make mistakes during your MBA education the cost is much lower than making startup mistakes in the real world.
Increasingly more of the best MBA programs have a strong focus on entrepreneurship. Of course, the academic portion of MBA programs must not be underrated, but most people agree that the structured mentorship and the chance to access the great resources these programs provide, are of invaluable worth. Successful investors and entrepreneurs and investors are drawn in to support students who would normally not be in a position to contact these business professionals. The startup world is extremely open to mentorship, but it would take many years to build up the same quality network that an entrepreneurship center, such as an MBA environment, is providing.
So forget about the popular idea that an MBA has not the same value anymore, and just look at the facts. The choice of going after an MBA is entirely personal. The best first action would be to talk to several people with opposing views, analyze the alternative possibilities and give some good thought to your long term objectives.