When we talk about human development, we can consider it as occurring in three phases. The first phase is pre-centric, the second is ego-centric and the third phase is a geo-centric. This is also sometimes referred to as prepersonal, personal and transpersonal.
The pre-centric phase is basically defined by the period beginning in utero through about the age of four or five, until which time a clearly differentiated sense of self has not yet developed. The ego-centric phase occurs from this point of differentiation, or individuation as Jung called it, forward through the lifespan. The world-centric view is a bit more elusive, developing as an individual begins to recognize that there is something larger -- a greater good, a bigger picture, etc.
In early development, the ego-centric phase waxes and wanes. From the point of individuation until about the beginning of the "tweens" there is a waxing or intensifying of "Me-ness" in a child. During the "tweens" stage of development -- when social connection becomes a priority -- the focus on ‘self' and ‘I' tends to wane to a certain degree. This ego-centricness once again intensifies through the period of adolescence; adolescence is typically defined as the teen years through the early 20s. Ego-centricity is particularly intense during the teen years, as anyone who has experienced the abject narcissism of a teenager is well aware.