is still callow, is still inexperienced

wet behind the ears, you are (or he/ she is) too young

he is still a naïve, a noob

is not available even in a minute quantity, is extremely rare or hard to come by

is not available even in a minute quantity, is extremely rare or hard to come by

nobody asks about anything

a closed mouth catches no flies, nothing venture, nothing gain

it is too early after a person's death (said when someone is impatient to inherit or behaves irresponsibly)

milk tooth

if not him then someone like him

satirically spoken to children who show laxity in education implying when when birds and beast can read, why can't the children of men do the same

A burnt child dreads the fire.

superstition knows no medicine