Congratulations on your pregnancy....I just delivered a beautiful baby girl 2 weeks ago! My son just turned 5 and we actually waited until 20 weeks to tell him about the baby. We actually just took him to the doctor with us for our ultrasound at 20 weeks as a surprise. In the waiting room, we gave him a gift bag with a few toys, a big brother t-shirt, and 2 pregnancy books (for kids obviously). Then, we went in and he got to see the baby and find out it was a girl. He was so excited and it was super cute for him to be able to see her and I think it made it more real for him, ya know? It was very hard to wait to tell him but well worth it. Plus, we only had to go through 4 months of when is the baby coming? Anyway, sorry to go OT but just thought that might be an idea for you of when to tell your DD.