Beginnings are vague things. Quite often you can't pin them down to one event you have to trawl back further and further through foggy past, peeling apart what ifs and untangling strands of memories.
Eventually one has to go all the way back to the start of the universe, and that's a question even the experts have to shrug their shoulders at. It's not like you can plug it into a calculator and come out with a balanced algorithm. At least, not yet.
But it is true that sometimes you can fasten down an occurrence or a moment or even just a single breath, like sticking a thumbtack through a dead butterfly, and label it as a 'beginning' in your mind. Identifying that one moment makes us feel secure, like maybe it was destined to happen instead of just being a random sequence of events that fed off each other and tripped over each other and eventually fell like dominoes to the unlikely conclusion.
Cvusscha Mistbane has pinned down a moment. Of course she knows that there are plenty of other moments that led to this moment, but this is the one she chose. She thinks that the moment she stood on shaky legs in front of the burning shell of her house was where her story began. Her cheeks were impossibly hot and her lungs were filled with dragging, choking smoke and the roof had just caved in with a dreadful, apocalyptic crash and blaze of sparks. All for a sword, a mere thing, made by man and used by man and nothing but steel. Her friend had said, "Come away now, Vuss. Come away. There's nothing you can do."
And she'd thought: No. No, there is something I can do. And I'm going to do it.
That's the beginning, in her head.
It led to finally leaving her home and having a heart full of anger and purpose (they balanced each other, kept each other burning and never sputtered out). It led to her standing before the greatest hero in the land and then meeting someone who definitely wasn't a hero at all but turned out to be the only person she'd ever really trust (or even love, if you wanted to go down that track). It led to her dancing with the faeries and slapping a vampire across his aristocratic fine-boned face and it led to her bringing down an entire kingdom. It led to her saving her grandfather, at least for a little while, and it led to justice and redemption and it led to her finally achieving something.
So yes, beginnings are vague things and technically don't really exist at all. But sometimes you can ignore the philosophy, and you can choose your beginning, and keep it in your mind, and remember it always, even when your bones ache and your hair is silver and your hands are thin and trembly, with visible veins like bluey-purple highways.