told my family about reunion - it didn't go well

Without knowing all the details of your relationship, as an adoptee who, like your sister, has never had an interest in tracking down my biological parents, my guess is that she is feeling protective. People can get pretty nasty when they feel that someone they love is threatened. It's "circle the wagons, you're either with us or against us." The #1 reason I have never considered it is that I wouldn't want to cause my mom even an ounce of pain after all she's given me. If I had an adopted sibling who made the decision you have, I'd probably go to war, too. (I hope I wouldn't be hateful about it, and you definitely don't deserve that, but I wouldn't be nice, either.) None of this is to suggest she's right and you're wrong. You have every right to make contact with your biological family, and as I said, I know basically nothing of the details of your relationships. My advice, as hard as it is, is to put yourself in her shoes and do your best to heal the rift. Best of luck!