We didn't officially tell Ella early on but we openly talked about being pregnant or a baby. Dave even had her practice saying pregnant one night. Even after I heard the heart beat at 9 weeks, I wanted to wait to tell her until we would tell other people because she's a blabber mouth. :)
As I got further along and hit 13 weeks, I talked to her more and more about it. I'd ask her if she wanted a little brother or little sister. She almost always said little brother.
I don't think there was one specific time we sat down just to tell her for sure that there would be another baby. We just talked about it a lot.
On Easter she got some books about a new baby. Her favorite one had both kids playing at a park. She talked about how she was going to teach the new baby to ride a swing. I asked her how and she said, "Hold on!" and held up her hands like she's holding onto a swing. Almost ever since that day, she tries to push younger kids on swings at the park.
Ella only sort of liked her dolls before. She'd like them for a day or two and then wouldn't. But now she's all over them. They have to sleep with her. She tucks them in for naps. They have to sit at the table when she's eating. She pushes them around in strollers and shopping cards all around the house. She has a lot of dolls because we got a lot from Kathryn plus she got 2 as gifts. I even have my old dolls to give to her. She seems so excited. She takes her dolls to the park and pushes them in the swing. She also tries to feed them. I have to wipe food caked into their mouths all the time. She has them sit on the potty. Sometimes she says they have to go when she's not even going to sit.