It is a process that usually happens between ages 10 and 14 for girls and ages 12 and 16 for boys. It causes physical changes, and affects boys and girls differently. ︎In girls : • The first.

puberty: [noun] the condition of being or the period of becoming first capable of reproducing sexually that is brought on by the production of sex hormones and the maturing of the reproductive organs (such as the testes and ovaries), development of secondary sex characteristics (such as male facial hair growth and female breast development),.