I understand all that pretty well, my daughter, who is in her early 20's, might be a kid, but she's certainly more mentally grown up than plenty of folks in their 50's that I know. I was merely making a wan remark about how at my age, someone in their mid forties, like Miss Coulter, looks very young.
The very real problem is that for the past 35+ years, people have been called "kids" or "young", who are long past being either. This, in turn, fosters immaturity and the nation and culture is thusly devalued; as are those words.