NTA good for you on standing your ground. You're literally not even a legal adult and you have so much life ahead of you. That your family is already pressing you to have babies is frankly gross. Enjoy your relationship on it's own terms, enjoy life on your own terms, get an education or a good job. Go to parties, meet new friends, do those things teens and young adults are supposed to do.

Maybe you were a little crude, and maybe you let slip an ugly truth about the way your sibs were raised, but basically... they asked for it. I wish more people who didn't want kids didn't have them, there would be less unhappiness in the world.

(For the record, I'm in my 30s, don't have kids, don't want them, and my life is great! Don't let people bully you into thinking that you have to have children to be fulfilled or happy.)