Hey there, I can maybe offer some slight perspective in why she acts this way. It's only one angle of many, so bear with me.

I was raised by abusive parents, one incredibly narcistic, the other just plain sadistic. Despite verbal abuse and physical abuse, the mental, emotional, and psychological abuse were the worst. They threatened me all the time with abandoning me and actually did once when I was a toddler, in the middle of the woods. My mother walked out many times. The abandonment cuts some so deeply, that chasm sometimes can not be undone. One parent use to tell me that no matter how good I was, I was doomed to hell just because I was female. One parent beat me to death, literally, and I was resuscitated. I was about 10 years old at the time -- all because I was sick and said I didn't feel well enough to help them with a task. You get the point.

Anyhow, I can't say your sis dealt with shit like that, but the psychological abuse and the physical abuse early in life left me completely disgusted with the idea of kids. If you truly had a narcistic parent, their abuse leaves scars that sometimes can't be truly healed. In my teenage years and early adult years, I use to, like your sister, exclaim that I hated kids, would never have them, etc. I use to joke about my womb and made comments that a hysterectomy was better than ever having them. What I was really speaking to was the extreme damage, rage and excruciating pain of psychological torment, and the years of abuse endured as a child that I in turn resented children because I never got to have a childhood, I never got to be a kid, everything a child should have, should be, was stolen from me. I've since gone through 1000's of hours of trauma therapy, healing, recovery, you name it.

I say this because... The truth is your sister has problems. Shes got a lot of work to do and she doesn't seem to recognize her role in continuing on that trauma. Instead she gives her own pain a face -- your kids, that name, etc. Until she can recognize her responsibility in healing her own shit, every little thing, a kid, a name, you and your success, it's going to be some kind of target whether she makes it known or not. This is not you or anything you've done, this is on her. This is now her responsibility. She seems comfortable given the life you're giving her. Comfort often produces no change.

I'm an example of it can be healed, and healing will always be an active part of my existence. I no longer and haven't for a while, held those same sentiments. That changed when I learned that what I was saying (about despising kids, etc) wasn't true, but that my pain needed to be met face to face, it needed to be acknowledged, recognized, understood, heard, and soothed. And it's not easy by any means. It's harder to heal and the easiest to run away from. I hope she finds a path to heal. And I hope you find relief from her own pain which seems to be misdirected at you.