Stage of life is a term used to describe the different phases of life that a person goes through. YOUTH (5 letters) is the period of life between childhood and adulthood, usually between the ages of 12 and 20. INFANCY (7 letters) is the earliest stage of life, typically from birth to two years old. AGE (3 letters) is the period of life after maturity, usually from 40 onwards. ESTATE (6 letters) is the period of life after retirement, when a person is no longer working. Postadolescence (15 letters) is the period of life between adolescence and adulthood, usually between the ages of 18 and 25.