Probably the biggest changes you’ll experience are changes in your body. The only other time your body changes this much and as quickly is when you’re an infant. Some people grow very quickly and others grow slowly, but by the time you reach late adolescence most of the slower growers will have caught up. Boys generally start to develop two years later than girls but catch up very quickly between the ages of 14 and 16.
The basic shape of our bodies changes as we grow and develop. Girls become more curvy, narrower at the waist, and broader at the hips and shoulders. Boys become broader at the shoulders and more muscular. Their voices deepen, especially between the ages of 16 and 18, and they grow facial hair. Both girls and boys grow body hair and develop sweat glands. Chemicals calledhormones control many of these changes.