Just Aagh

Okay, this is a real question that I have.

Whenever someone does an activity that they were a little too cowardly to do before, they say something like, "I finally mustered the balls to go ahead and try this" or whatever

But I am a girl, and I don't have "balls"...so why do I partake in this overused phrase?

(That is not the question that I have actually though so don't try and answer it please and thank you)

Anyways, so since I am female, as I previously stated, should I (if I say anything at all) say "I finally mustered the boobs to go ahead and try this"?

I just feel like this makes more sense.

I understand having balls makes males more of men, but I am a proud female, and I don't want balls, nor do I need any. So, since having breasts makes a female more womanly (and I just want to say that being a woman is a heck of a tough and most of the time awesome occupation, so why wouldn't I want to insinuate something womanly?) wouldn't you say kind of what I suggested above?

Now that's my question. And I hope to get some answers.