I Am Not Close With My Sibling

This isn’t a post where I’m looking for likes, it could well be I am in the wrong. I consider myself to be a good person but in this situation, I’m not sure anymore. I have a sister who is two years younger than me. As the elder sister I was always taught to play with her and be nice. I always found her to be a cause of trouble, and somehow this was always my fault. We both had a tough time with bullies in school, but I didn’t want to be treated differently so I kept quiet, kept going and left school with qualifications enough to provide me with a long and rewarding career.
My sister took a different route. She complained bitterly about everything and anything, never finished school, fell pregnant by the first boy she met who she brought on our last family holiday against everyone’s wishes. She then had to be rescued from a violent relationship. Had another child then seemed to stop making any effort. She would rarely dress or wash her hair, and our parents cared for her children. He second partner then left her. Now she is ill all the time, and piling on weight to levels that are dangerous.
And where was I? I was traveling around the country with my work, trying to improve myself beyond my struggles at school, trying to be independent so my burnt out parents had one less challenge, trying to make friends and date in each new town I ended up in.
And how do I feel about my sister? I resent her for ageing my parents, I hate her for playing the victim so casually when she is only a victim of her own choices. For how long must the world carry her? And what about her poor children? I feel like I will never be able to speak to my sister in any way but anger. And I know that’s terrible, I know that hurts my parents to see to sisters, their children driven apart. But despite the fact I know I’m a good, understanding and compassionate person, the one person I cannot forgive, the one I will never forgive, is my sister.