When to tell people?

So this will be our second... our first is only 5 months old, and this is a complete surprise, however we are super excited about it. We know our families will probably be a little judgy, but plan to tell them after 8 week ultrasound when we know all is well... we are struggling already about how we are going to keep it a secret for 12 weeks from everyone else... so my question is when do you ladies plan on telling people? Also when to tell your boss?