Is it possible to sign for a marriage but not register it until 4 months later

We have booked our church wedding but it is not an auspicious date for marriage in the Chinese calendar. My parents say it's bad luck to be married then. So we are organising a Chinese tea ceremony 4 months earlier on a good date, but my parents now want a celebrant to officiate and for us to sign and register then, but my bride doesn't want that date on our certificate. Can we sign, but not register it, and just wait for the church wedding to be officially married?