Someone once asked me if I shaped my rocks before I polished them.
"How do you choose their shape?"
"I whisper to them and they tell me."
I was kidding.
The fact is, I start by removing rough edges, grinding away at cracks and valleys. Then it's quite obvious how to shape the rock.
Perhaps this is something like being in a relationship with a loving creator. Only He knows our shape from the start. But he gradually smooths us, patiently removing uneven surfaces until it becomes quite obvious, even to ourselves, what our perfect shape will be.
Not that I know a whole lot about the subject. Just thinking.