Absolutely. Trig is classical era, and Warhammer seems to be a steampunky Renaissance level of tech. There is no way to do good land surveying, which you need for good maps, without trigonometry. Sailors' navigation instruments rely on trigonometry, and it is foundational for serious architecture and engineering of many kinds.
Speaking as someone with a degree in economics: you don't need calculus until you start trying to rigorously prove a lot of things, and even then if you're willing to fake your curves into straight lines for just good-enough approximations you can do it with basic geometry. I suspect that a lot of what Mathilde has learned is finance, which is a distinct but related discipline (covering things like "accounting," "how investment works," and "how banks work"), but which also you don't need more than algebra to do at a functional level.
(I wonder if Warhammer has double-entry bookkeeping? It became popular among European mercantile/banking interests in the fifteenth and sixteenth centuries, which is about the analogous time for Warhammer's tech/cultural level afaict.)