Tell or don't tell?

I have a group of 4 besties, 3 of whom are currently pregnant. I've just found out that I am too, and I can't wait to tell them after the 6 week scan. Problem is, I live in a different state and will see them next when I go over for one of their baby showers. I want to tell them 2 weeks before I go, rather than while I'm there, so that I don't steal her thunder. My DH thinks I should wait until after the shower, because he thinks that telling before will steal her thunder anyway. I probably won't see them again until she's had her baby in January, and I don't think I can wait that long to celebrate with them. Is this selfish of me? Should I tell them before I go, or wait until after?