Hi Jen,
I have to be honest with you and say that for me, the last day of each teaching assignment was the worst. It was so hard because for the last few weeks of each assignment, the classroom was mine and I had the students full time. I got to know them, their likes and dislikes, their habits, their abilities and it becamse so hard saying goodbye. Each class sent me off with the most amazing gifts, speeches, and memory books and it was so hard.
On the first day of school, the kids will be so excited to have a student teacher! I remember my students kept looking at me and came over to my desk and asked lots of questions. They helped me to feel at home in their classroom.
What grade do you have again? If you have younger kids, maybe you can take a bag with you that has Mickey on it. That way, you can look at it and smile, knowing that Mickey is your graduation present and that you are one day closer to having your own classroom!

The kids can look at it and say, "Hey, she likes Mickey Mouse!" and that might help break the ice with them..... Just a suggestion. (My kids went gaga over pictures of my dogs and that became the ice breaker for the first few days. They would ask about my dogs and ask if they could meet them. )
Jen, you are going to do a great job! I know you're a bit nervous.... Just take some deep breaths and know that we are cheering you on!

Also, if you have any questions, feel free to ask.
Good luck at weigh in tomorrow! You are doing a great job and I bet the scale will show it!