Try thinking of being the zeroth person in a line. Or your child being in the zeroth year of her life.
How many lions are in my room at the moment? Hopefully zero.
But zero sheep is not a flock.
(Besides, there's uncountably many things you have zero of in you room.)
> But zero sheep is not a flock.
So one isn't a natural number?
> (Besides, there's uncountably many things you have zero of in you room.)
;) Exactly. Zero is the most natural number.
By the way, your point about polynomials works in favour of the convention that 0 is a natural number.