Im about to have the same situation except i have a 3yr old and a 2yr old due anyday
Hello:) im a first time mum with my little one on the way and i live with my sister who is a single mother with a 4 month old and a almost 2 year old, when she first showed her little boy hes new sister he acted totally different then what they expected he was so protective of hes little sister and still is loves her to death, the easy way is just to ease them in, in a nice warm and carm enviroment, everything will work out fine as long as you are patient and carm, my sister finds it very hard to cope with two little ones only because she has no patients and she has a short temper, if you bring your little one into this world in a preparing and relaxing and carm enviroment im sure you will cope very well if your little girl listens to you, you will have no problems, goodluck and message me if you have any questions:)