Generally speaking, when parents die, sons should be filial for three years. In feudal society, they were officials in North Korea, and they could also take three years off. This is called keeping the system. In return for the kindness of parents. During the mourning period, you are not allowed to participate in entertainment and celebrations. If you participate, the court will reduce the crime and punish you. So there is a saying that you are not allowed to participate in wedding activities.

Due to the influence of filial piety for too long, the people have adjusted themselves to a shorter period, and there have been sayings of one year, one hundred days and seven days.

Actually, it depends on whether you attach importance to it or not. It doesn't matter if you don't pay attention. Of course, if it's your own funeral, don't bring taboos to your friends. It is best to attend the wedding in 100 days.