I will offer just something to consider, since you're asking. Though definitely do what makes you guys happy. Every baby should be celebrated, no matter how long it's little life here may be! But I also don't feel like it's bad to celebrate it in my heart for however long need be when there's no comfort in announcing early, you know?
One thing I didn't realize until it happened was that it does seem to make a difference if you have people around you who can understand (as in, experienced it themselves) pregnancy loss. There really is a support you need in that situation that can only come from people who've been there. I can't really describe it, and who knows, maybe it's not that way for everybody, but I've been there a lot and it had continued to ring true for me, anyway. The only pregnancies out of my 11 that we have announced right away have been ones I ended up losings, and that was hard because I have few to no people who really understand. If I had more family and close friends near me who knew exactly what I was going through, I'd probably feel a lot more comfortable telling people early on. (also age groups are a factor, if you hang out with a lot of others your age. I had my first losses for no apparent reason in my very early 20's and I was like a freak of nature to those my age...well, being married freaked them out anyway, but wanting a baby in the first place, and then LOSING them...it was as if I was the first person experiencing miscarriage that they'd ever encountered! Even at 27, most are "weirded out" to know I've lost 7!)
The other consideration is that un-telling isn't simply announcing loss. It's a matter of dealing with the fact that the GOOD news seems to travel at lightening speed, while the bad news seems to barely make it around, because people are uncomfortable talking about it (which makes me sad...miscarriage is just as real as anything, it's not taboo). So at least in my experience, it feels like EVERYONE knows about the pregnancy almost instantly, but after a miscarriage, the same people who the good news spread to quickly will have no idea, and the hard questions like "how far along are you?", "when are you due?", etc can keep coming for MONTHS. Granted, I don't expect everyone to always know about my life, but it has been pretty consistent IME...I know a lot of people who immediately go out and start talking about pregnancy news, but those same people aren't comfortable with sharing the unfortunate news of loss.
So those are just thoughts from someone who loses more than she keeps, and I'm not trying to be a downer, I just wish I'd had these things to consider years ago (doesn't mean deciding not to tell, just considering ahead of time) rather than learning them in hindsight.