Should we say something now?

We have been ttc for 2 years and for the last 6 months have been doing <a href="">iui</a>. We recently discovered we are pregnant. It is still early, my missed period will be Saturday. We did 4 at home tests with positive results on Saturday and Sunday. Then on Monday we got a blood test which also was positive. The doctor prescribed progesterone to help baby secure. We are so excited because we have been trying for so long. Not everyone in family is aware we have been trying for so long. 
So here is the question:
We committed going to a family trip to Ireland in July and well now that's our due date. Do we tell the family now or wait a few weeks to be sure the pregnancy took?