As per the comment above by NiceOrc this is likely The Adoration of Jenna Fox, published in 2008 by Mary E. Pearson, as answered in http://scifi.stackexchange.com/questions/96687/existential-book-about-girl-resurrected-by-nanotechnology and http://scifi.stackexchange.com/questions/80103/short-book-involving-a-car-crash-and-artificial-humans. I think the review here provides a better summary:
Jenna is the miracle child, her parents' angel, the perfect child who excels while inside she silently protests, only to show minor rebellions at sixteen. After a horrific accident and a year in a coma, Jenna wakes in an old house in another state, with no memory of herself or what happened. She recovers quickly, but wonders endlessly about who she is. There is only her mother and her grandmother, Lily, in the big old house that they moved to from Boston, and Lily doesn't seem to like her at all. She speaks of Jenna like she's another person, somewhere else.
As Jenna navigates her way through the act of living, watching old movies of Jenna growing up while snippets of memory slowly surface, her questions only grow. Why can't she walk properly, why don't her hands interlace? Why is the scar under her chin missing? Why is her mother so frightened, so controlling? Why must she hide from the world?
The truth is staggering and frightening: her entire body is synthetic, and only ten per cent of her brain is from the pre-accident Jenna. She a lab project of her father's, a billionaire doctor who invented Bio Gel, in which organs can be housed indefinitely if kept at the right temperature. Too cold and Jenna will expire. Kept at a moderate temperature, and she could live hundreds of years, never visibly ageing. The implications are profound. Is she the real Jenna? Is ten per cent enough? Was she ever enough for her parents? Is it even ethical for her to be alive? And what makes Jenna dangerous is the fact that she's illegal, and shouldn't even exist.