age more than 65 years age 4 to 12 years old age 10 to 15 years old adolescent normal physiological development between adolescence and middle age altered growth and development infant, postmature age more than 45 years age under 30 years middle age normal growth and development for age age 15 to 34 years old age between late 20s and early 40s age more than 55 years tall for age body height normal for age term infant age 6 to 23 months old age more than 60 years age 10 to 46 years old childhood age 20-40 years age 10 to 30 years old age under 60 years old age 20-70 years aging problems age under 25 years age more than 50 years