Can the engagement date be set at will?

That won't do. If you don't believe in the Gregorian calendar, you'd better set a better date. You can't pick Tomb-Sweeping Day or April 4th. It looks unlucky. The solar calendar says, when is the auspicious day of the ecliptic, what to do and what not to do. Of course, it doesn't matter if I don't believe it, but I think it's best not to take bus No.4 during the day. After all, it sounds unlucky. Of course, it depends on your belief. If you really don't believe me, of course I'm an atheist, and it's okay for two people to fall in love. These are secondary, but I think it is difficult for your parents to get along with her parents. I wish you happiness.