Dr. James Hollis thinks about life in two halves.
According to him, the first half of life is focused on the external world and fulfilling societal expectations. It's the time when you grow up and let your ego drive your decisions and actions. It's a period when you are unconscious and unaware of what is driving you and why you want the things you want.
Unlike the first, the second half embodies a perspective shift. In this half of life, one's focus is on the inner world and our quest for meaning and purpose. It's a time of becoming aware and conscious of one's psyche, self, ego, and thoughts. A time when one contemplates the things they want out of life and questions the norms and beliefs held previously.
To me, the order of these two chapters is fixed, but the time we need to move from one "half" to another isn't. It's up to you when you start your journey of contemplation, reflection, and awareness. The sooner, the better. Your real life starts in the second half.