Getting pregnant the first time you have sex
A woman can get pregnant after her first ovulation (has had her first cycle). This means a woman is fertile and can get pregnant before her first menstruation.
After her first ovulation, a woman is fertile for about 6 days each month. A woman who has sexual intercourse during her fertile days can get pregnant. Even the first time she has sex.
A man is fertile when he has an ejaculation for the first time. He produces semen for the first time during puberty. A man can make a woman pregnant. Even the first time he has sex.
If you do not wish to have children use contraception.