A human’s understanding of death evolves through each of these stages as research would confirm

A human’s understanding of death evolves through each of these stages as research would confirm. A great determining factor as to how quickly a human passes through each stage is actually their maturity level. Another factor is life experience that also plays part in how quickly one passes through each stage.
The age limitations are just an estimate, for example, a child that is perhaps 7 years in age and has never really been outside the home nor watched TV and then loses a loved one for the first time, well they would go through stage 1 first because this is their level of experience and maturity. On the other hand, a child that is faced with their own life-threatening condition may view death in a far more mature level, way beyond their age. They tend to have a more realistic approach to death and what it means.