I know many people here believe that the state have like that when they have kid but I believe they're formed from human personality/perception.
Like GOV was canonically created when the colonies got together and decided to create a government.
The vid:
So since the states/colonies/personas are formed by human perception of that area, or the will they see when a state is formed it's because there's enough people to fully form and Idea of what the future will be these will be in genral very conflicting ideas so most states start looking like teens before gaining statehood or development if a solid political ideal (/governing body) in which they become adults.
From their they have "kids" the conflicting ideals don't go away so some states may become heavily divided on the ideals once these ideals also form a voice or become to strong they will split from the state and become their own body around the age of 5-9.
Now understand if two states have the same ideal in a similar area (state of Jefferson for ex) they can split at the same time creating this ideal which will be very young around 3-4 due to being formed but not of the same state yet same area.