As you have not clearly mentioned it, I presume you do not have prior work experience. Hence my advice is on these lines.
If an MBA is a must for entrepreneurship - the answer is definitely no.
With regard to your business idea - glad to know there is someone who is finding it good enough to invest.
Whether to take up the entrepreneur / business route right away please see if you can find answers to the following:
1. How unique is your business idea? Do you see a first mover advantage?
2. How disruptive is your idea or is it just a better shade of any existing business model / product / service etc?
3. Is your business idea - market situation / current economic scenario / technological advancement specific - or it can wait and be implemented at any time?
4. Post what level of scrutiny has the person(s) elicited their interest in investing in your business idea?
5. How much time and what kind of resources would it require to develop, test and go live with your business idea and start generating revenues? (Remember - investors will look for your revenue / monetization strategy).
6. What is their upper time limit / investment monies they will be able to support you with - in case at the time of implementing your idea you face certain obstructions / delays etc. And, are you ok with it?
If the business idea is not that unique, it can be done any time etc. - be doubly sure about your RoI and then jump into it - not just because you found an investor for your idea.
As far as MBA is concerned - learning should be a lifelong process. If you are looking at entrepreneurship (or even employment for that matter) - the advantage of gaining some real time work experience and then doing a program like the one you mentioned is far more beneficial. You just don't ready some theory but are able to apply it to your real time work scenarios.
In the context of what you had asked, I recollect his quote attributed to Shri Ratan Tata - "I don't believe in taking right decisions. I take decisions and then make them right".
Wishing you the very best!