Alice is at an age when adult expectations are being placed upon her and she doesn’t fully understand what they are or what they mean. Being a girl, she is eager to fulfill these expectations, as boys would not be, so her struggle to understand is especially poignant. The white rabbit, whom she follows into the hole, is one of the more starkly allegorical elements of the story. He represents adulthood as a destiny. Everyone will become an adult. As such, he is full of cares and fears and is always checking his watch, as it is time that brings adulthood closer.
The central question of the story gets posed by the caterpillar: “Who are you?” Alice answers that she doesn’t rightly know. Is she an adult? Is she a child? She doesn’t understand what it means to be either and can’t answer the question. The caterpillar instructs her to eat the mushroom, telling her, “One side makes you taller, the other makes you small.” Alice, good girl that she is, follows the instructions and grows alternately enormous and miniscule, again, symbolic of her predicament in which she is simultaneously a child and an adult and can’t control how she is seen in any given moment.
Wonderland is the adult world turned upside down and revealed for what it really is. Everyone here is mad because they accede to adult norms and conventions that are inherently absurd. The Mad Hatter’s Tea party is a case in point. A Victorian tea party is the height of formality, having strict codes for deportment and even what can be discussed. Alice tries to observe those forms and finds it just doesn’t work anymore. Those codes come back to her as arbitrary and absurd, which, of course, they are.
There are several mother figures in Wonderland who are also inversions of the norm, the Duchess who beats her son for no reason and the ironically named Queen of Hearts who is arbitrary and cruel instead of loving and warm. Mothers, who demand and enforce conformity to the absurdity of adulthood upon emerging adolescents, seem especially cruel as they shed their former warmth as indulgent mothers of children.
Alice’s final revelation, “You’re nothing but a pack of cards!” is both rejection and acceptance of the adult world. Like the adult world, a pack of cards is ordered, ranked, and regulated. Having a healthy appreciation of the absurdity of those orders and conventions is what’s needed to enter adulthood without going mad.