My husband also doesn't understand this not telling anyone until 12 weeks thing! Both our families know, but he's already told several of friends while I haven't told any of mine yet... he just doesn't get it! I'll be sharing the news after my scan too.... kinda nervous to do so though!
I'll share the news at work after new year, although my manager already knows. There's a pregnant girl at my work who LOVES being centre of attention and I don't think she'll be too happy to hear my news as it won't all be about her anymore haha. She seriously turns every conversation into it being about her being pregnant...
Thing is quite a few people know now but it's telling the kids that worries me I think. It'll suddenly be a lot more real. My youngest said to me this morning while I was getting dressed ' It looks like there's a baby in there! You've already got 3 it's illegal to have 4!' Kind of guessing she's not overly keen to give up the baby of the family title!