Learn English – One word for a person who doesn’t act before thinking

The word is pessimist, a person who expects the worst.

Mr X is a pessimist.

Contrast with optimist.

It is often said that while optimists are happier, pessimists are more often correct.

and

Optimists are said to live longer than pessimists, though a pessimist might say those extra few years are bound to be miserable.

Yes, there is such a word. It is arrive.

arrive

(of a baby) be born: he will feel jealous when a new baby arrives.

[Updates]

You can consider using the word materialize (which probably can provoke laughter and provide amusement). "... and I materialized nine months later."

materialize

intr to become fact; actually happen ⇒ our hopes never materialized

to invest or become invested with a physical shape or form

to cause (a spirit, as of a dead person) to appear in material form or (of a spirit) to appear in such form

intr to take shape; become tangible ⇒ after hours of discussion, the project finally began to materialize

(physics) to form (material particles) from energy, as in pair production