Family issues

So my dad's family has never been supportive of me. My parents separated when I was 4. So I've always been closer to my mom's family. I told my father I was pregnant and he was okay with it. I'm only 18 and had just graduated high school at 4 weeks pregnant. He told my stepmom and she changed his opinion on it. Now they act like it is a disease. I'm so excited about my pregnancy and so is my boyfriend. My dad is making me tell his parents and sister. I wanted to wait until I'm 12 weeks. I'm only 9 weeks and have to tell them today. I'm dreading it. It is the first time they are meeting my boyfriend and I can't stop stressing about the meeting. 😕😢