Getting along with my sister is like walking on egg shells

Hmmm, that sounds a tad troublesome. So she victimizes herself, gaslights rather than admitting she is wrong and apologizing, and has people being extra careful around her. If that's true, I wonder why she is so insecure and defensive to this extent. Surely there's a better way she can deal with her issues?

I have a brother like that. Minimize the time you spend with her and talk with her. When it becomes possible to do, cut her out of your life but make her think it was her idea to cut you out. lol. Best thing I ever did for myself.

I count my words I say and the time I spend with my sibling.

Sometimes my fiance is like that.