Spending too much money on your first short is a big mistake.

While everyone can't do it, many people in my experience are spending too much money on their first short film. Since you're probably not making it with the intention of getting your money back, you want to create a good showpiece to get to those bigger projects.

Spending_Short_Film_Director_James_Kicklighter

However, it shouldn't be at the expense of wrecking your personal finances (if you're independently wealthy, this doesn't apply).

Many times in my career, I have observed filmmakers who put too much stock in a singular project, only to see them not go any further.

It's okay to fail, I fail often; it teaches you the most. But if that failure is at the expense of wrecking your career before it has even begun, then you should evaluate. I discuss this and more with Film Courage in the interview above.