We all know what modern kid's books are like. The main character is a 'rebel' who thinks her parents are mean, everything is unfair, and who spends her dinnertime crying in her room, all the while being a jerk herself.
From the very first pages of A Little Princess, you can tell Sara Crewe is of a different breed.
She is only seven at the beginning, but already her father is her best friend, she's very polite, and completely unspoiled by her father's riches. When she has to stay at Miss Minchin's Seminary for Girl's, although she doesn't want to, she stays without complaint.
Sara has an imagination. She is kind to three most shunned beings at the seminary; Lottie the crybaby, Ermengarde the school dunce, and Becky, the slave-like maid. Even when the misfortunes of her father's death and the loss of her fortune strike, turning her into a penniless orphan, she is still polite. Her version of rebelling against Miss Minchin's keeping her like a slave is to not rebel, which infuriates Miss Minchin. She even swallows her pride and and accepts a sixpence from a boy mistaking her for a beggar!
Of course the plot is entertaining, and has a happy ending involving the finding of her father's friend and the return of Sara's riches, but the real jewel behind the story is Sara herself, who is a real role model while still staying on a human scale.
So long, modern books. I'm sticking with Sara.