The executive branch is composed of the President, Vice President and Cabinet members. President The president is the head of state, head of the U.S. government and the commander-in-chief of the U.S. military.
Menarche. The average age of menarche, or first menstruation, in the United States is 12.88 years for Caucasian girls and 12.16 years for African American girls. A popular misconception is that menarche marks the beginning of puberty; in reality, menarche occurs later in puberty.
Report Abuse. It's more age dependant than weight dependant. The average age for menarche (first period) in the UK is 12 years and 11 months. A girl can start her periods anywhere between the ages of 9-16. Being very underweight can sometimes prevent menarche or delay it.