Frost grew up in Anchorage, Alaska. Prior to the 1964 Alaska earthquake her family home was four blocks from Cook Inlet; afterwards it was only two. This experience of the dynamic Earth led her to study geology at Dartmouth College, where she completed an undergraduate honors thesis in the Salt Range of northern Pakistan. She earned the PhD at the University of Cambridge in 1984. Her dissertation, using isotopic tracers to investigate sediment provenance and granite petrogenesis, underscored the important role of crustal recycling in the geochemical evolution of the continental crust.