As with anything, it requires a bit of explanation.
Their name is a portmanteu of ball girls in spanish and latin, which eventually evolved into a very similar word to Chicuela, which ironically is a mexican slang for girls.
But beyond that, chicuelas are the females of this world, they initially are thought of fantasy anime girls.
Having said that, the main diference is that they don't reproduce like we do, neither they grow as we normally do.
Their reproduction, since they lack males in this world, is more a magical version of how ants and bees reproduce.
Some females are granted by divine luck, the ability to become queens, which are then tasked with the ability to produce eggs, similar to birds or reptiles.
After they are born, they're taken to the town nursery where they hatch after a couple weeks of incubation, and the fist phase, phase 1, starts.
Chicuelas beyond that are not much diferent to our anime normal girls.
The other main diference is that they don't age normally like we do.
They gather experience in their phase, until they suddently evolve in a few seconds to their next phase.
This evolution is caused by some trauma, like pain or extreme anger or by the use of their correct elemental crystal.
Ages therefore are not a correct way to cathegorize them, but phases of evolution would be a more proper term.
Phase 0 is similar to an egg.
Phase 1 to 10 are similar to human ages.
0, 5, 10, 15, 20, 25, 30, 35, 40, 50, these are the corresponding human ages to the chicuela phases.
They also should follow something similar to how videogame levels work in a rpg.
Each new level should increase their physical skills until phase 5, after that, their mental stats and stamina keep evolving, but their physical skills would cap around phase 5, only their knowledge, luck, charisma, and mana power should increase up to phase 10.