When to announce???

I am curious about when everyone is announcing they are expecting?  I am currently 13 weeks and 1 day.  This is the longest a pregnancy has gone because I had two previous miscarriages.  I am just so nervous and never feel comfortable about saying anything but I am starting to show a little.  Also, I have not had a detailed US since 7 weeks and then at 11.5 weeks were unable to hear baby I guess Bc of position but could see a heartbeat and baby doing flips on a basic US.  Please can I have advice?  Next appointment is not till the end of month :-(