Graduate work in economics requires a lot more math than people think. The key to success is to take as much math as you can. Get started early if you can.
The math requirements for master’s programs vary, but they pretty much all require serious calculus and some statistics or econometrics. Many programs require more math.
PhD programs all require additional math, at least through linear algebra. And many require math through real analysis and often more work in statistics. For both MA and PhD programs some basic computer programming is helpful, but not necessary.
By the way, these same courses are excellent prep for future work in finance, data science, health sciences, and pretty much any science field.
EXTRA TIP : Get to know some econ faculty. Faculty members are delighted to talk to about graduate school in economics. They’ve all been there!
Lot’s more advice and info: https://www.aeaweb.org/resources/students/grad-prep