i have a 4,5 and almost 7 year old step children and the one i just had is my first. its easier once you learn your baby and his/her patterns. ive only had my little one home for about 5 days and things are going smoothly. just make sure you arent so focused on the new little addition that you arent paying attention to the other little ones. (not that you would) try to let them help with age appropriate activities. like letting them get you a diaper or a burp cloth. things that are easy. they will love being able to help plus when they are helpful and praised for being so, it boosts their confidence even at that age. i find that if they are actively involved it makes them more willing to accept the new sibling. but relax, and have fun learning about your new little one. he/she might surprise you as will the other two siblings. :) good luck momma.