There is always a before. Sequence is not bound by time. On the hypothetical spaceship leaving earth at the speed of light, the lives of the people on earth SEQUENTIALLY are completed before the lives of the people on the spaceship are completed.
Which came first ZERO or something?
This really is a non-question. The appearance of sequence has very much to do with time and surprisingly the 2LoT.
There is no space and no time before the beginning (in inflationary theory wrt this universe, the big bang).
Timelessness in this sense is often called "eternity" by believers - which scientists tend to mistake for infinity, which is a useful mathematical construct but doesn't translate well to physics and is not what we believers mean when we say "eternity". We mean what it is, timelessness.
The bottom line is this: all cosmologies (whether inflationary, imaginary, multi-verse, brane, cyclic, ekpyrotic, etc.) require a beginning because physical causality must have geometry. But the void in which there is a beginning has no space, no time, no energy, no matter, no logic, no physical laws, etc. and especially no physical causation. A beginning requires an uncaused cause, first cause, prime mover, i.e. God.
On spaceships and earth - velocity and time, you might find this helpful: SpaceTime Wheel