We don't have complete details; everything we know comes from "The Impossible Astronaut"/"The Day of the Moon", "Let's Kill Hitler", two brief mentions "Summer Falls and Other Stories" (anthology), two of the stories in "The Legends of River Song" (anthology), and "Imaginary Enemies" (comic story).
- She was taken away "within a month".
- We know very little about her first years, except that the Silents had something to do with raising her (which is why we know very little, because her memories from that period were "a bit of a jumble" thanks to their powers), and she arrived somewhere in America somewhere in the 1960s.
- From 1967 to summer 1969, she lived in the closed-down Graystark Hall Orphanage in Florida, still being raised by the Silents.
- From summer 1969 to January 1970, she lived as a transient on the run.
- In January 1970, she arrived in Manhattan, regenerated into Mels, and was quickly found by the Silence, who resumed her training (although we don't know where, or whether Silents were involved).
- From 1970 to the late 1990s, we know nothing, except that her apparent age didn't increase.
- From the late 1990s (whenever Amy and Rory started year 3) to the early 2010s (whenever the present-day scenes in"Let's Kill Hitler" happened), she lived somewhere in Leadworth. It's not clear where exactly she lived, or with who, until a year after school, when she somehow ("it's complicated") owned a flat. During this time, she clearly aged like a human.
Meanwhile, "Summer Falls" implies that some of this may have been changed since we originally saw it. In late 1969, post-Angels Amy tells a journalist that she and Rory have been donating money to a dilapidated orphanage in Florida for the past couple years, and that she plans to write a book about a little girl lost in New York. Who knows how much she got away with changing?