A WGA script officially confirmed that Rey's flashback shows that she was left on Jakku with Unkar Plutt who's a king of scavengers.
A little girl. Rey as a child. She is sobbing, hysterical.
Unkar Plutt's meaty hand holds her thin arm. She is on Jakku,
watching a starship fly into the sky, abandoning her.
No, come back!
If that's the case, presumably he started her off on a scavenger path, and "watched" over her by slowly starving her via smaller rations.
There is NO current canon indications (at least in the film, Foster adult novelization, Visual Dictionary Rey related pages) to confirm or deny that:
She was intentionally slotted into being a scavenger. However, this is a logical outcome on a planet full of scavengers.
She was watched over or protected.
There is SOME ground to guess that she lived elsewhere before the AT-AT, because there just aren't enough "scratch a day" scratches on her wall calendar to last more than a couple (2-5) of years (source: I actually did a counting estimate from the film), and the flahshback shows her to be ~5 years old, around 15 years prior.
DISCLAIMER: I didn't yet read the Rey-centric tie in YA book. There may be some clues there, but I strongly suspect not, since this is clearly as closely held secret as Luke's parentage in Episodes IV and V for Disney.