The use of the word "balls" in the above phrase is quite correct. With that being said, I do not believe it wise to use it in any kind of professional conversation. You may use it with friends or people you are quite familiar with, but definately not your boss.

I believe that it was only used in the show you watched for emphasis. Phrases like "the courage" or "the nerve" or "I dared to" are more appropriate.

I agree with the above comments and am pleased to see you've decided not to use it.

There's another aspect of the word I wanted to point out.  The phrase originated to mean "Stand up and 'be a man'.  Grow some balls."  This indicates that having the courage to do something takes a "real man".  Therfore, the use of "balls" can be construed to be a sexist term.

  Daniel:

   Twenty years ago  it would not have been acceptable. Today,  it is   acceptable to many  more people.

  A more sophisticated person would say or write:   "I had the courage to make the decision."

  At it's worst,   "Balls" is not highly offensive.  

   I would  use it perhaps  if I was seething with rage.   I would not write because when writing for the public, I always want to be seen as occupying the Moral High Ground  and the High Ground of articulate and objective thought.

Not only is it vulgar and rude, the verb in the sentence is wrong. Decisions are made. You can take the initiative or take a stance.  The word "guts" is not much better. 

English is replete with excellent alternatives. Courage is a great word.  Have the courage to make the decision to scour sources for more appropriate choices. 

You should probably say 'I had the guts to make the decision' I think. That's quite a common way to put it professionally.