Girls generally have their first period between the ages of 11 and 16, and when the first period comes, there is usually an increase in secretions, a feeling of swelling in the pelvis, and sometimes a slight swelling of the breasts
In fact, there is not much else that can be characterized by a girl's breasts, but she may be emotionally unstable and lose her temper, and so on, and these are all signs that may be before the first period.