Beware of Asteroids!

[Deantwo]

With the servers being offline, is the impact date also pushed forward? Ours is supposed to be arriving today but it looks like we won't be able to do anything about it at the moment.

Impact date is a date, not an amount of time.
So if the servers are down, the impact date doesn't change.

Rather or not the asteroid will be prevented from spawning or will be skipped if the date elapses while the servers are done, I don't actually know.
The asteroid is commonly unpredictable, some times it plain vanishes and never shows up, or cities don't report its existence until the last moments.

Best I can say is that if you are hit by it, feel safe in knowing that another won't impact that avatar again. Only one asteroid ever appear per avatar, and only on that avatar's original homeworld.