Aelia was born while we were inside my time-accelerated God Kingdom. As such, her mental age should be around nine years old at least.
However, monsters' aging wasn't as straightforward as that of normal humans!
For example, Ember's physical age as a slime was roughly five years old. But in slime age, that was already at the level of being a grandmother, or someone approaching a hundred years old in human age.
Aelia, during the short time we spent inside my God Kingdom, spent twice as long as Ember had lived—a total of nine years! In slime age, she would be way beyond 100 years old, but with her body being humanoid right from the start, her mental and physical aging was slowed down, reaching the same rate as a normal human.
What I want to say is that ten years was too long for some monsters' senses. It was enough time to go from the 0th stage up to the Divine Conqueror Level.