How does one become an ambassador?

One of my daughters (Fly) is interested in becoming an ambassador someday. She’s pretty passionate about politics and wants to work in the field, but has zero interest in actually being a politician. Instead, she’d like to work in some capacity that influences politics, but more behind the scenes.

She’s a junior in high school at the moment, and plans to major in International Relations and Political Science when she goes to college. What courses outside her major would be helpful? Is it necessary to be fluent in one or more foreign language? (She’s taken 4 years of French, but I doubt she’s fluent.) What kind of career path would best position her for her ultimate goal? Or is it really just a matter of being in the right place, at the right time, and having friends who might run for President someday? ~