My girls are 31 months apart so almost three years. My oldest was terrible even when I was pregnant, she used to kick my belly and tell me she didn't want baby sister to come out. And when I brought my new baby home she ran up to me and hit me as hard as she could right in my cesarian incision! I was devistated! As I fell to my knees in pain I wondered what was the appropiate way to deal with this new change in my perfect first born! I of course wanted to lash out because she hurt me and I was in so much pain and astonishment to her reaction! But I slowly got back up and explained to her that she hurt me and that I had a BIG owie, and that I loved her VERY much and I promised her things would be ok. She also just feel deep into the terrible two's! Worse than she already was, she doesn't mind at all, and really acts out in public! It's very hard! One thing that did happen for the better was my oldest suddenly wanted to be potty trained! She became competely potty trained in about a week!
So now my baby is almost 4 months old and things are a lot better, however it can still be very hard! I also find that I'm asking my oldest to wait ALOT! I never thought of what the other moms have suggested in telling the baby to wait! That's great I'm going to have to try that one!
Some things that have helped me are doing my best to get the oldest involved in taking care of the baby, explaining that the baby's needs are much like her needs and that mommy is doing to best she can to take care of them both so that they stay healthy and happy. She seems to understand that well. I also make sure I spend one on one time with my oldest and do special things with her that she knows the baby can't do, like bake, and go swimming, and coloring. The next milestone will be getting them to share a room, Autumn (oldest) refuses to let her sister sleep in HER room, lol. So you see there will always be ups and downs, and stress like you've never felt before in your life. But we as mommies are strong and will always conquer!
Good Luck and Congratulations!