I never went into her past here (not that I remember) but, yes, Abby is a cyborg, and she always was a cyborg against her will for roughly half her life. Her old memories are repressed through tech and she she is, in some ways, a different person now (she does have some "muscle memory" and traits from her previous life she displays).

Referring to herself as "It" or "This One" is based in some slight uncertainty of her self-identity. A "disconnect". And it is meant to be self-depreciation. But as said, she won't dwell on the past, the present is good enough for her.

Abby is available for questions! Feel free to ask her stuff if you want.