How small was the universe before the Big Bang and what implications does this size have on our understanding of the origins of the cosmos?

Well, sweetheart, technically speaking, the universe before the Big Bang was practically indescribably tiny, like a super dense cosmic dot ready to explode. Its size challenges our understanding of the cosmos because it begs the question - how did something so small eventually become so ginormous? But hey, that's the fun of science, it keeps us on our toes.