December 25 in the West is equivalent to January 7th in Egypt. Christians celebrate Christmas in Egypt on January 7th while they celebrate it on December 25 in the West. It is a matter of calendar calculations and not creed!
It is not fair to impose the Egyptian calendar on immigrants who live in a country different from Egypt. Thus, the solution is easy: we start the nativity fasting earlier and unify the date of celebrating Christmas on December 25.
The Coptic Christians may celebrate the feast on January 7th as well accepting diversity which doesn’t contradict with our faith. Concerning our Coptic calendar, I would say that it is not applied even in Egypt where the Islamic calendar is more applicable and the Arab identity is embraced. Yet, the Coptic identity is hidden inside the Copts. I’d say that we should celebrate Christmas on December 25 since all the Copts don’t live in Egypt and the Coptic calendar is not applied.