I'm always a bit hesitant when people ask about authors' personal details like age or birthdays. With Freida McFadden, the information isn't plastered everywhere, which honestly I respect. From what I've gathered piecing together interviews and her bio, she seems to be in her forties or early fifties. A birthday isn't something I've ever seen confirmed, and it feels a little invasive to dig for it, you know? Her focus is so clearly on the thrillers, on those twisty plots. I'm here for the books, not the birth certificate.
That said, you can sometimes get a vague sense of an author's generation from their cultural references or the tech in their novels. The worlds in 'The Housemaid' or 'The Wife Upstairs' don't feel like they're written by someone super young; there's a certain... seasoned understanding of domestic tension and long-held secrets. But that's just my reading between the lines. Maybe she prefers keeping that part of her life separate, and that's totally fair.