Because marriage, pregnancy, and childbirth are difficult experiences that can be very traumatic for young girls, who are likely to be at an age in which they do not have the capacity to assimilate all the consequences of marrying or having children. Besides, young girls are more likely to be coerced into marriage, or abused, meaning that their legal rights would be violated in these situations.
Inge is using the defense mechanism of repression, Repression is rejecting a painful experience, memories and more likely when you see the person or thing which caused that to happen.
