I’ll get downvoted to oblivion but YTA. Not for not wanting kids - just for your answer. You don’t have to be so freaking rude. Your sister’s questions come from a place of love. She just wants her kids to have cousins & for you to discover the joys of motherhood. Many people end up changing their minds. In her mind it’s the best thing that’s ever happened to her and she wants you to discover this happiness. Maybe it’s not clear to her that your decision is final. What not explain that to her sweetly?

So that you’re set on your decision to not ever have kids - that’s fine. But it doesn’t make you NOT an asshole to snap like that during a video chat and bring up abortion like it’s no big deal. How needlessly violent to say “i would abort it and you would never know”. Why get so worked up? She’s not saying that to hurt you. Justify it all you want - on Reddit, you might get crowned for your sass but in the real world, you’re an asshole.