Delaying childbirth is common in western culture. We often delay having a family until we are well established in our careers. However, women need to be aware that their breasts do not fully develop until they give birth to their first child. This means that having your first child before the age of 30 and breastfeeding can help decrease your risk. In fact, breastfeeding can even rewind the biological breast clock to a lower risk level if your first child is born after the age of 30.