I’ve been thinking of it this way:

It is a mystery and the only way to experience God is through faith and the life that results from that faith. Reason/thinking can’t get us there.

Jesus was also fully human and humans have to learn and grow. So he went through a process of discovery.

If a major component of original sin is anxiety, Jesus had none. He replaced it with perfect faith. Over time, he discovered that he was the only begotten. Maybe he looked back on his life and only then realized that he always knew.