When to tell dc1 that dc2 is on the way?

[seriouslynonames]

Dc1 is 4.5 and I am 15 weeks with dc2. Don't want to tell her yet as quite a long time for her to wait and still worried that something may go wrong. how / when have others told older child? Obviously wouldn't be thinking about it if age gap was small!
Thanks

My dc1 is 3.5 and we told her when I was around 15 weeks, after all the initial tests came back and everything was ok. Of course there are still risks and still a while to go but we wanted her to have time to get used to the idea and try to bond with her soon to be sibling. I am very obviously pregnant at 19 weeks so people know immediately and say things when I am with her so I'm glad I told her.

My dd1 guessed at about 15 weeks with dd2 pregnancy (aged 4) and age guessed again this time (now 10) when I was about 4 weeks. I didn't deny it but asked her not to tell dd2 who's 6, we told her after 12 week scan x

My dd is also 4 1/2 and I'm 14 weeks, we have talked about the baby but haven't actually told her yet, when I am big enough and she asks I will say I'm growing a baby but my dd is the type to nag constantly day after day as to when the baby is coming so will leave it as late as possible with her!

We told our eldest after the 12 week scan when others were going to know. He was 4. Didn't occur to us not us tell him to be honest

I am 20 weeks now and we told our 4.5 year old son when I was about 14 or 15 weeks I think. He's mildly interested and seems to understand the baby will be born near his birthday in the summer.

We told DD1 at the same time we told family as didn't want her to not know when others did and in case any conversations were overheard.
She was a couple of months away from being 5 and quite mature and as we were only telling family at the time asked for it to be our secrect which she loved and did really well (we knew there was a chance she would tell others though).
Most of her friends have younger siblings and she has been asking for at least a yr when she could have a brother (not as keen on a sister at the time) so we knew she would be really pleased about it.
I think at 4/5 they understand a lot more than we often give them credit for

I told my 7 and 4 yr old as soon as I'd had 12 week scan I wanted them to be one of the 1st know . If you've told other people they may talk about the baby in front of dc and at 4.5 she will probably be earwigging your conversations and it's probably not nice for her to find out 3rd hand so to speak. Make it special give her a copy of the scan photo that's especially for her in card from baby saying can't wait to meet you something like that.

We have been asking our dd if she would like a brother or sister (brother she's decided) and we have said that we might so we have talked about it and what might happen so she doesn't mind other conversations about it which she hears because it's become part of our conversations with her. But I still won't tell her that we already are expecting as she doesn't understand the timescale and she will ask constantly and daily why it's not here yet.

We told our 4.5yo DS when I was 5w due to been constantly tired/unwell and he was very worried that I was sick. We told him that there was a long time to go and that if the baby was out too early, there would not be a baby. He was happy with this. I'm now 25w and he speaks/cuddles/kiss my bump