Each year I try to start with First Day Jitters by Julie Danneberg.
I love this book because I can remember what it is like to start a new year with new people in the class. Not sure if you will have a friend in there with you. The kids love that even teachers feel nervous about the first day. As a follow up activity, my class makes a First Day Jitters book. They write about what they were nervous about or what their first day was like. We compile these and add their pictures to the book. They continue to read this book throughout the year.