Incipient
Etymology
From Latin incipiens, the present participle of incipere, "to begin, take up," formed from in-, "on," and capere, "to take" (as in "capture"). To begin was, in this metaphor, to "take something on." English adopted it for whatever is barely underway — the moment a thing has started but not yet declared itself.
adjective · /in-SIP-ee-uhnt/
In the earliest stage of coming into being, just starting to appear.
What it names
The word for the first faint hint that something is beginning — an incipient smile, an incipient crisis — the stage before it has fully arrived or become obvious.
Example
She caught the incipient panic in his voice before he had even finished the sentence.
Related idea
Nascent suggests something already growing; incipient is one step earlier, marking the very first flicker of a beginning.