senior
ageist
eldership
of age
oldishness
seniorly
youthless
seniorlike
ageistically
old-farrant
mannish
venerable
grownish
grande dame
boomer
act one's age
old head on young shoulders
yealing
age like a fine wine
wise beyond one's years
gerontic
vicenarian
elderdom
twentysomething
dote
big
subsenior
agedness
ageism
cheeser
agelessness
nonsenior
grown
mutton dressed as lamb
oldling
adultocentrism
elder statesman
ager
gray
millennially
tricenarian
maturish
codgy
senile
elder
generationally
senilism
venerability
dodderer
aetat
geriatric
agerasia
beyond one's years
senescent
vetustity
chronophile
dry behind the ears
seniorness
dried up
age
look one's age
adultist
young adult
big enough and ugly enough
of a certain age
old folks
bluehair
adultcentrist
badge-cove
anile
elderliness
æt.
oldster
progeroid
auntie
ageistic
no spring chicken
peer
time-honoured
time-honored
dinosaur
oldness
old person
zayde
J. Random
adulty
OK, boomer
geezer
didine
golden