] She's just a kid.

From what I know of the period, kids were generally outside the world of people who counted. They were either noisy and spoiled, like the Middleton children, or they were much more well mannered like the the Harville's children in Persuasion, but they were notable for how well behaved they were. Young people counted after a young woman was out or a young man home from school. People might love their children or younger siblings, but this appears to be the generally accepted rule. To focus more than that on your children seems to suggest an unbecoming pride and selfishness--as it does in Lady Middleton and in Fanny Dashwood.