It’s different at the various grade levels. Some teachers may see their first class leaving the building for another school; some may see their first class graduating from the school district and moving on to other stages of their lives.
Whatever the situation, you’ll probably find that you think back to your first year for many school years to come. They will be the group that, for better and for worse, helped you complete your first year in an extremely important career.
Take a few minutes, before everyone dashes out your classroom door, to thank them. While you’ve been the teacher, they have taught you many things, as well.