In Downton Abbey, Daisy and Thomas's ages are a mystery that I believe is linked to enforced chastity, which serves as a tool for bodily control and infantilization. Carson accepts that the boys have sex (except for Thomas) and decrees that the girls must say no, otherwise they are prostitutes (except for Mary). Thus, by enforcing chastity in the kitchen, mature, free, or autonomous sexuality is denied, and the series' institutional system succeeds in stripping them of their adulthood. Patmore controls Daisy with shouting and orders, and even decides who her husband will be; the result is a mother-daughter relationship that the audience applauds and values. It reminds me of the traumatic attachment relationship between Janine and Aunt Lydia in "The Handmaid's Tale." Janine and Daisy are women, and they behave like insufferable children; this is how their minds protect them from abuse. Daisy, trapped in an asexual limbo for 15 years, is carefully constructed so that the script ensures the audience doesn't perceive her as a woman with her own desires; otherwise, she becomes someone like Ethel, facing expulsion, prostitution, and misery. This is the same logic as Gilead, where women's purity is not a moral choice but a social imposition to keep them docile to the system.
In Thomas's case, the forced chastity is much more violent and explicit. His sexuality is a crime and, in Carson's words, an aberration of nature. Thomas lives in terrifying abstinence, since any minimal encounter ends in blackmail, beatings, or the fear of prison (the wall in Gilead). Thus, while Daisy's adolescence stretches like chewing gum, Thomas's stretches or shrinks according to the circumstances. If Thomas cries alone in a room, he is a child who needs protection; But if he betrays Gwen at the dinner table (a "terrorist" act in the style of Mayday), he becomes a resentful, bitter, and Machiavellian man who deserves punishment. By suppressing the expression of their desires, Daisy appears too immature to demand better wages and Thomas too unstable to ask for respect.
