before someone's time
larva
prematurity
prematureness
off-time
unripe
early childhood
untimely
previous
prematurely
late
later
stadially
sexual maturity
youth
early
advanced
forestage
fixation
regression
arrested development
infantile fixation
transyouth
evolutionarily
behind
wet behind the ears
recapitulate
premature
primitive
be a hundred years too early
postembryonic
unripely
prematuration
minority
jejunely
evolved
immaturely
delayed
precocious
earliness
juvenescence
oversoon
pregenitality
young
inchoate
go off at half-cock
point of no return
inarticulation
go off half-cocked
rareripe
time
intrastadial
underdeveloped
babydom
hypomature
interstadially
hypermature
adultescence
aborning
break
greenly
interstadial
ahead of time
chronogenetic
state of the art
rudimentary
neoteny
embryotropic
drekly
tough tuchus
childish
tough titty
adolescent
spring
gentle
prepubescently
tough cookies
immaturity
unfledged
overboom
tough toodles
infantile
die on the vine
anticipate
youthhood
unthoughted
twinkle in one's daddy's eye
maturity