used in connection with sb who is still young and does not have much experience 在少不更事的…岁时；在不谙世故的…岁上
He left home at the tender age of 15.
他 15 岁离家，还少不更事。
She shouldn’t be having to deal with problems like this at such a tender age.
她小小年纪涉世未深，实在不必应对这样的问题。