extremely enthusiastic (adjective) gung ho: full of enthusiasm
Sinonime: adolescent, blooming, blossoming, boyish, boylike, budding, burgeoning, callow, childish,
childlike, crude, developing,
early,
fledgling,
fresh, girlish, girllike, green*,
growing, half-grown,
ignorant,
inexperienced, infant,
inferior, junior, juvenile,
little,
modern,
new, newborn, newish, not aged, pubescent, puerile,
punk, raw,
recent, tender, tenderfoot, undeveloped, undisciplined, unfinished, unfledged, unlearned, unpracticed, unripe, unseasoned, untried, unversed, vernal, youthful
Antonime: mature, old, older