Time has passed, and in that forest the boy never gets "old"
So that he could "Forever" live as the God's Wife...bride... wife coz he's the bride??
In the forest, they never get old so it was not visible how 100 years passed... They could live forever there not getting old
i think it's more like, time passes slowly in the forest, that's why it took Taro a hundred year to reach adolescent. Taro, being completely fullfilled and happy , he didn't bother counting the years.
i must be slow or skipped over some stuff bc i do NAWT understand chapter 6 like wdym 100 years