Why Am I Not Panicking After Transmigrating into a Poor, Sickly Noble in a Book?

[Western fantasy + steam magic] When Nangong Yujin hears an NPC nearby mocking her before she has even opened her eyes, she knows she's terribly unlucky: she's transmigrated into a book, becoming Ophelia, the tragic heroine who goes from a duke's daughter to a commoner and then gets betrayed by her childhood sweetheart. The classic NPC mockery from the start, her childhood sweetheart's hypocritical face as soon as she looks up, and even a cold-water scene worthy of cultural heritage status… But it doesn't matter. Though she's been reduced to a commoner and has a frail body, at least she has the forbidden magic book she acquired after transmigrating into the book. Her body may be frail, but the forbidden magic book in her hands is anything but weak. And so, in this age of steam magic, when nobles scheme against one another for power and the royal family is in decline, a destitute, frail noblewoman gradually becomes the unusual stationary mage at the heart of the storm. “Yes, she is physically frail and seems very delicate.” One interviewee described her this way: “Objectively speaking, you could knock her over with the slightest push.” “But that's only if you actually get the chance to touch her.” (There is a romantic pairing, but the story focuses on the plot. The romance develops naturally and isn't forced, with the goal of letting the chemistry emerge organically from the exciting story.)