It was a pleasure to burn, in the end. Sarah had known it was coming without being told. Knowing things without being told was all part of being a witch, she supposed.
She hadn't ever chosen, as such - but rather she preferred to let the currents and grooves of the world guide her path through it. And the world had chosen for her to be a witch.
To anybody else, this might have seemed like a state of affairs that could be analysed and considered - weighing up the pros (foresight; cackling) and the cons (burning) - but for Sarah it was simply the way of things. She could not compare it to anything, and she saw no point in doing so.
Some say that the burning is the making of a witch, and I'm inclined to agree. It's probably for the best.