""I was a complete pain in the neck as a teenager/20 something. ""
I know it's moved on, but I have a similar issue in my family.
My eldest went through what sounds like a similar time as you. My youngest will never forgive her for the spoilt family times, the ignoring of everyone's Birthday, except hers of course, expecting everyone to drop their boundaries, the utter selfishness of it all etc. My youngest is of the opinion that we'll never get those times back, especially now my Mum has died. Also that she shouldn't have been subjected to that behaviour.
She doesn't care if my eldest does a complete turn around, she won't forgive her.
I don't get involved because she's entitled to her take on it all, I don't want to minimise how my eldest made her feel.
My middle DD is only just realising the effect it's had on her and now she's in her 20's she is LC.
Reading your posts, there is definite resentment and anger (and a form of hatred) towards you, if you want to sum that up as jealousy, then so be it.
People who are being very harsh towards your Sister have never lived with someone close as you were, behaving as you did around them for so long.