On the contrary! B-schools are increasingly giving importance to the non-profit sector, as well as to CSR. You will bring a very valuable perspective which will be very different from what a Goldman guy will bring in. And if you llok at the class stats of the top b-schools you will notice they take in people with Humanities background (if this is what you have).
What will really matter is: whether you took up some real responsibilities and made a positive impact on the people you were working with. You will also need to articulate clear career goals and the need for an MBA to fulfill these goals.
Ask us about our interview prep service