How do I tell my family I'm pregnant when they already know?

I'm Nineteen at 10 weeks. I told my Grandma and she insisted on me getting married which I disagreed on. I told a couple cousins. I'm sure my whole family knows now! My dad told me not to make it an announcement. I've brought my boyfriend to the last two parties. I've noticed when I say hi they look at my belly. Everyone is being nice to my boyfriend and I. I have a pretty big family who are very traditional. Family is half White and Peruvian. First and youngest girl to have a baby. I don't know if they all know for sure but I think they do. I just am afraid once I tell them they will act different maybe? Should I just carry on like nothing? I will pop before Thanks Giving which is the next big holiday I believe.