Molly had been beyond anxious that she wouldn't be able to handle having a half-demon child but Zachary ended up being more angel than demon. He only cried when he needed something and learned how to sleep through the night alarmingly fast.
Aside from that, he seemed to be following basic human milestones so she wondered if he was going to age at the same rate she did rather than living hundreds of years like his father. It was still surreal after all this time that things ended up the way they did for her if she thought about it too much. It was better to accept things at face value.
She had a husband and son who adored her and that was more than she ever anticipated having considering her family of origin. How it happened didn't matter as much as the end result.
Zachary grew to be an extremely curious and surprisingly articulate toddler. By the time he was three, he was able to speak in complete sentences as if he was a much older child.