People avoid taking "big actions" for fear of "big failures." But what makes a failure big or small? Truthfully, it doesn't matter.
When people talk about a "big" or "small" failure, they refer to the magnitude of effort, not the severeness of the consequences. Minor actions too can cause catastrophic effects. Here the effort is less, but the severity of the result is high.
Similarly, a 5-month project involves a lot of effort. But its failure might not have any real consequences except the learnings needed to succeed the next time. In short, don't pay attention to anyone making fun of your "failed efforts" that have no real consequences.