Synonyms for early:
half-baked, untimely, precipitous, soon.
on time (adjective)
foregoing, introductory, earlier, preceding, avant-garde, anteceding.
sooner than expected (adjective)
betimes, too soon, beforehand, prematurely, ahead of time, soon.
puberty, girlhood, initially, Since, childlike, pester power, boyhood, date from, barely, grow up, preemptive, Ere, developmental, grow up on, front end, the earliest, development, stripling, juvenile, upbringing, all along, youth, infancy, prematurely, adolescence, first-time, school-age, pioneer, childhood, Pre-, date back to, originally, first-ever, mornings, pre-existing, leadoff.
beforehand, ancient, childish, opening, minority, hangover, historically, retrospective, forerunner, previous, holdover, before, timeline, prior, predecessor, babyish.
ahead, Toward, near, primary.
sooner than expected (adverb)
immature, untimely, precocious, punctual.
Sense 3 (noun)
barely, Since, before, prior.
Sense 5 (noun)
all along, opening, antediluvian, front end.
Sense 6 (noun)
Sense 7 (noun)
historical, date back to, historically, retrospective.
initial, precocious, primordial, ahead of time, primitive, opening, beforehand, first, untimely, prematurely, primeval, too soon, ancient.