Who Have You Told?

This is our first pregnancy so we are very excited. We had a wedding this past weekend and his family is a bunch of partiers and when I am with them I generally follow suit. I knew it would be obvious to the "fun" cousins that I was not drinking - they all have been on pregnancy watch since the holidays so we decided to tell his parents in case the beans were spilled. Of course our table of cousins caught on that I was "faking it" with my ginger ale n lime wedge and called me out on it. So they know and are excited but they also know it's way too soon to be sharing it with others. I just have a feeling they told everyone.... We are opting not to tell his sister just yet although we know she will be excited, she is one of those "expert" parents that forces advice & experiences on everyone n also believes google over doctors - coo coo.  She will find out before the masses but not until we are ready plus I don't want my nephews to know too soon, god forbid something happens. How do you explain a miscarriage to a 5 yr old?