My 4 year old has started with the questions....

Hi everyone.... Well, it finally happened. My daughter asked me if she was born from my belly. I was quite taken back but then knew this might be coming. When we were on vacation, the couple who rented the beach house next to our's had a young son and she 8 months pregnant. Our children played together on the beach and my daughter was real interested in the woman's big belly. The woman told my daughter that there is a baby in there. My daughter seemed to get it and said to me, Mom there is a baby in her belly. I said yes sweetheart, there is. Almost 5 days later, after we returned home from our vacation, I was watching the Discovery channel show, "Make room for Baby". My daughter came into the room and sat next to me. I tried to change the station but she said she wanted to see the baby so I left it on. When the baby was born she said, "Look Ma, that baby was born in the hospital just like me" and I said "that is right sweetheart". She said "and that baby came out of her mommy's belly just like me". I smiled to her and said, "sweetheart, you were born in my heart and you came from P's belly (I use her first name). She said, I came from P's belly and I said yes. She said "oh". I said and H (our new son who is 9 months old) came from S's belly. She said "H came from S's belly", and I said said. She remembers S as we just had a visit with her not quite a month ago. I said do you remember P (we just saw them in the beginning of the summer). She said yes. I said, "come here sweetheart, do you want to look at your life book and see a pictures of P and of H's bmom S? She said yes, real excited. So I took her little hand in my mine and we pulled out her life book and her brothers life book, from their closet shelves and I turned the pages to when she was born. She was real excited. I told her, look here is Mommy and Daddy and you and P. Again she said, I came from your belly Mommy and I said, you came from P's belly and H came from S's belly. I pointed to a picture of P with her big belly and I said, see that big belly, she said yes, I said that is where you came from. She said oh, I came from P's belly and H came from S's belly. I said that is right. She said you came from Nana's belly and I said right. After we had our little talk, I asked my daughter if she would like to talk to P. She said yes, so I called her number and let T speak with her. Her bmom was shocked when T said to her, "I came from your belly". She asked me if I told her and I said yes. I don't want to lie to her about something like this. My daughter took it all in stride. She walked around for the rest of the day saying, I came from P's belly and I kept smiling at her and telling her how smart she is and how beautiful she is and how proud I am of her. Later when my dh came home (I caught him outside to let him know what was happening) and when she saw her daddy, she was so happy and saying, I came from P's belly. Daddy said that is right and your such a smart little cookie. For the rest of the day and the entire next day, she kept telling me, she came from P's belly and I kept reaffirming that and telling her how much I love her and how proud I am of her. Later that night, after tucking her in and reflecting on it all, the worry starts. I love her so much. I hope I'm doing this the right way. Sometimes I worry about telling her things when she is too young. I wait for her to ask tho, I never lead the discussion yet. I feel if she is asking, then she needs to know. Has anyone else dealt with this at such a young age? I have to admit, she took it completely in stride to me, no sadness, no look of confusion, no in depth questions. Just okay Mommy and onward she went, for now. Maybe starting young is okay. Maybe she will never be shocked by it all and will just take it in stride, at least, I hope so. I also felt a strange sense of relief to have the type of relationship I have with my children's bmom's, to be able to call them and have them reinforce what I have told the children. Instead of feeling powerless, I felt empowered and able to give my daughter what she needed, at this time. No lie's, no secets, no shame, just a warm voice on the other end of the phone confirming what she just learned in a postive and loving way.