Have you ever started a not-for-profit organization? What did you learn?

I am thinking about starting a not-for-profit organization to support parents who have experienced trauma. I am currently a graduate student in Public Health and am taking Management of Non-Profit Organizations otherwise I probably would only think “wouldn’t that be nice to do someday?”

So have you ever been a part of a starting-up not-for-profit? Have you been on a Board of Directors? What did you learn? What advice would you give?