It is good you made some progress, making some amends is likely healing for you.

Though I do not know what is going on in your sister's head (pride?), years and years ago, when I was unable to attend my brother's wedding (it was overseas), he didn't talk to me for 10 years! We do talk on a more regular basis now but I tend to not call/reach out to people when I am feeling depressed (don't know if she has depression issues?) IMO, when people do not reach out to us, either, we have grown apart (though family should make some effort, this applies to friendships) or they are dealing with their own issues that may have nothing to do with you. Do you think your sister is as emotionally aware as you are?

Also, perhaps my brother felt I owed him more of an apology for not going to that wedding (I probably should have been more sensitive--I can think of a few times I have accidently been insensitive to my friends when I was younger/had more friends) but after years went by with him refusing to talk to me, though his feelings were probably hurt, my whole family thought he should have been willing to talk to me despite what happened....