My Sisters keeper

Hi for my English class I am supposed to write an opening of a chapter for "My Sisters keeper" in the voice of Kate. It takes place right after page 47. Can someone familiar with the novel and the conventions of the English language please take a look?
"I was six years old, I was awoken violently feeling a pillow held firm to my face, the air being drained from my body, my lungs screaming. An unknown assailant was on top of me, it felt almost like my sister; but it couldn’t be… she loves me. I felt the pressure on my face drop and heard the voice of my dad scolding my sister. I looked up and and saw the pillow in her hands. I wish she finished the job.
Ever since my diagnosis when I was two years old my life has been a downwards spiral; that is to say I have a life all. Every day it’s a constant cycle of taking medicine and going in and out of the hospital. At what point do we separate living from surviving? I have a beating heart but I have no identity of my own. I am my disease.
My parents treat me like a princess, probably because they knew they could lose me anytime and I won’t be able to come back, sometimes it feels like too much. My sister acts as if she loves me but I know she despises my existence as she knows it the purpose of her existence. "