Elena,
You said:
[...] it also seems rather unlikely that the big bang happened of its own accord. Just one day the universe said, "Hey, Im bored. Why not have a Big Bang?"
Aside from the question of what, if anything, caused the Big Bang, the way you portray it indicates that you have the wrong idea about the theory behind it.
The universe couldn't have said anything prior to the Big Bang, because it
wasn't there. The Big Bang was when the universe first came into existence. In fact, one cannot even speak of 'prior to the Big Bang', because time itself, as an inalienable part of spacetime, was created with the Big Bang.
"It's amazing what you can learn from DNA." - Desdamona.
™ Version 4.2