A little anxiety?

Since we found out we were pregnant, we told our children about it. They both seemed very excited, though the Little Guy went through a short period of hitting my belly and saying, "I don't want the baby." That only lasted a few weeks. The older child has been so excited, coming up with names for the baby, preparing a place for the baby to sleep (some blankets and a shoebox - how cute), and kissing my belly. Recently however, she has been acting quite out of character. Lil' Miss has always been a moody one, but it has been off the charts lately. Today, every little thing set her off - either into a screaming fit or a ball of tears. I am thinking that even though she is excited about the new baby, she still has some anxiety about upcoming change. I wonder if she is unsure of what her place will be in the family. Maybe wondering if it will be another brother - she finds the one she has to be a bit overwhelming. Maybe wondering if it is another girl, where does that leave her? I am not sure what to do about this new behavior. Of course, we will still act in the firm way that we do and expect her to be respectful and obedient. However, I feel led to have a heart to heart with her and find out how she truly feels about the coming baby. I don't know how realistic it is to have such a conversation with a young child, but hopefully I can alleviate some of her anxiety. I also will make an extra effort to spend more one on one time with her. As I've posted before, time is hard to come by - I am still as exhausted as I was in the first trimester, but making sure my little girl is emotionally okay must take precedence over sleep for a little while.