Son compartido

Am I the A hole for refusing to let my sister bring her pet iguana to my wedding? My (28F) fiancé (30M) and I are planning our wedding, and everything was going smoothly… until my sister (26F) dropped a bomb. She insists on bringing her pet iguana, Mr. Scales, as her “plus-one.” I explained that the venue doesn’t allow reptiles, and honestly, I just don’t want a cold-blooded lizard crawling around during the ceremony. She flipped out, calling me “heartless” and threatening not to come. My parent