The legal age of marriage is the lower limit of the marriage age stipulated by the state according to the actual situation, and its purpose is to protect the legitimate rights and interests of minors and their healthy growth. The setting of legal marriage age will affect the marriage choice and the first marriage rate of minors.

In some countries and regions, the legal age of marriage is relatively high, which may cause young people to be unable to get married before the legal age of marriage, thus having a certain impact on the rate of first marriage. However, in some other countries and regions, the legal age of marriage is relatively low, and young people can get married earlier, but the rate of first marriage is not necessarily high.

The rate of first marriage is also influenced by other factors, such as social and economic development level, education level, female status, gender equality, marriage concept and so on. Changes in these factors may lead to changes in young people's attitudes and ideas about marriage, thus affecting the rate of first marriage.

Therefore, although the legal age of marriage has a certain relationship with the first marriage rate, the first marriage rate is affected by many factors, which need to be analyzed and discussed from many angles.