I don't think that's the opposite of what she means - sounds to me as if she's talking about bland, non-threatening, and not voicing opinions that might be considered startling.
Kate M, to me, would be the epitome of "classy". I think of her as infinitely well turned out, endlessly polite, not rocking the boat, knowing where to tread.
Someone who, at some point in middle age, may well be spotted drinking gin with a straw, weeping gently whilst polishing the silver. Lamenting the fact that they have always been a lumpen size 14, and wondering whether this is the reason no one shows her affection except the dogs; because in every other way she followed all the rules, and yet her she is.
On the other hand, they might be the one who, at a great age, takes huge comfort in the fact that they're still a size 6, and still fit into their wedding dress, because, honestly, having standards was the most important thing in their lives, and they don't understand quite what happened..... why they followed all the rules and yet now have nothing tangible to show for it, and none of her family visits unless she issues a three-line whip.
Sorry to go a bit dark, but I have both these characters in my family!