I can't wait to tell mine either. They will have no idea as they are 11, 9 and 8 now.
We are pretty sure my oldest saw the pregnacare vits in the kitchen cupboard when making himself a hot choc in Jan, but may have forgotten now. I was a week or so away from telling them last time when I had the MC, that was 2 days before mothersday, and OH and my sister and my mates got me some flowers, so they thought I did really well for mothersday (but I looked like a panda). So will tell them after the hosp 12 /13 week scan time, couldn't bear to see them upset if anything happened.
My little one (my daughter) is soo desperate to share a bedroom like the boys, I am trying to work it so the boys end up on their own and she can share with the baby, even if a boy for 5 years or so till older. (it is def her turn!) It might even help her calm down and grow up a little.