Learning how to use magic was something one learned even before making the first step, even before one own first word.
Such was the reality for the humans that lived upon the world they called Edvigla, in the end, it was a question of being able to adapt and humans excelled in just that.
It wasn’t something to a degree where parents had to fear their son or daughter would torch the whole town, it was more something like them making float small objects around.
Aside from that, as Thirteen himself experimented, using magic was a tiring experience, and the burden was heavier as the complexity and power of the magic used grew.
Normally one had to build up stamina, in a similar way of physical exercise the use of mana allowed one to exert greater spells or a higher number of normal ones.
The upper limit was, for a normal human, represented by how much mana he was able to store in the first place.