Today we will consider class and, to a much lesser extent, ethnicity.
In An Old-Fashioned Girl Alcott romanticizes what used to be known as genteel poverty--your better-quality people who have fallen on hard times or perhaps have just never had much in the way of disposable income. Polly Milton comes from just that sort of background. She hasn't been exposed to wealthy adults who encourage materialism in their young and who enjoy seeing children imitating adult behavior. (Something that many would argue hasn't changed since Alcott's time.) Whether fourteen or twenty, Polly is full of so many good qualities that seem to be a product of her poorer upbringing--She knows how to have good, clean fun making candy, how to empathize with those who are even poorer than herself, how to get over her envy of others who have more, how to remake last season's clothes, how to respect and admire her elders, how to play in the snow, how to make others feel good. These things either come naturally to her or are taught to her by her poor but noble mother "whose dress never was too fine for little wet cheeks to lie against, or loving little arms to press." Polly's fine manners don't come naturally to the wealthy Shaw children, whose own mother, Polly believes, doesn't have a "right motherly heart" and didn't teach her young to stand when Grandma enters the room or to show proper sibling love toward one another.
The Shaw children's father is a man of business who worked his way up from humble beginnings to an upper-class New England life. He is a very sympathetic character; his early poverty is a big plus and, presumably, is the reason he recognizes Polly's sterling qualities and hopes they will rub off on his own daughter.
Polly's kind of poverty is placed on a pedestal. Another figure in the book suffers from much more serious want. Jane Bryant (whose name, I think, is sometimes Jenny) is a seventeen-year-old girl who is alone in the world and unable to make enough money to live. She finds her situation so dire that she tries killing herself. But even here we have a romanticized ending when she is saved by the "old and homely, and good and happy" Miss Mills and befriended by "dear, kind" Polly.
Polly's kind of poverty is good. Jane's kind of poverty is bad. But the very poor can benefit from Polly's attentions just as the very rich can.
How good is Polly's kind of poverty? There is only one path to nobility for the Shaw family. They must become poor like Polly. In fact, you could argue that Polly's eventual mate only becomes good enough for her when he loses his money and becomes noble and poor like she is.
Except for Jane/Jenny, we don't see a lot of truly poor characters. The few servants who appear are Irish women who are portrayed as weak or even cowardly. In a warm-hearted intergenerational scene, Grandma Shaw, who is everything you could ever ask of a grandmother (though I don't think she bakes) tells the children a story from her childhood in which she refers to her family's servant as "our own stupid Biddy" and then goes on to make fun of her, including an imitation of her brogue. Neither Polly, nor the third-person narrator, object to this.
Legend has it that Alcott and her family nearly starved one winter when her father made his ill-fated attempt at communal living. She also served as a nurse during the Civil War. She was the main source of support for her parents as well as herself. This is a woman who experienced real poverty and saw real suffering. So what's going on with the glow she throws around Polly? (And, to my recollection now, the March family in Little Women?) Is it a coping mechanism to make her own past more acceptable? She also romanticizes the elderly (Grandma Shaw) and the West (Tom goes out there to make his fortune and comes back so brown, healthy, and manly). Is this some kind of Victorian thing? She grew up in a Transcendental culture. Does romanticizing the common person in the form of the poor (but not too poor) have something to do with that philosophy? Or was Alcott a shrewd marketer who was writing to an audience?
You still see elements romanticized in children's books today, particularly eccentric small town characters and the elderly. Not so much poverty, though. I think that with the advent of photography and film and mass journalism, the realities of poverty are all too well known, even to children. Today's child readers might have a very hard time accepting An Old-Fashioned Girl because they know too much to buy into the joys of being poor.