first shoutout to all the lovely 30+ yo characters in main or major roles 
we don't have enough of them!
second here is how i draw my 30's kids

they don't have exact ages but the guy is "late 30s" and the lady is "early 30s"... close enough?
on that topic, while people do age differently, overall it doesn't seem that stuff like wrinkles and silver hair settle in until like sometime in late 30s or 40s. But that's just an observation?