Congratulations on your new job! 3rd grade is wonderful!
Yes, it's very normal to have first year jitters - it's the excitement, anticipation, etc... The funny thing is...... the kids will be just as nervous (if not more so!) than you. Have you read the picture book First Day Jitters
? Too funny - you HAVE to read it. I even read it to my kids on the first day of school.
As far as what to do to get ready. Here are some ideas:
1. Call another 3rd grade teacher and see if you can get together this summer. Think of any questions you have and jot them down for her/him.
2. Go to your state's website and see what you'll be teaching. Print out a copy to keep. I keep mine in a folder so I can refer to it when needed.
3. Call your school and see if you can get a copy of your school's textbooks. Look back at the state framework and see if the textbooks cover what you'll need to teach. That lets you know what extra resources you'll need to use.
4. Ask the school what supplies they already give you (many offer office supplies to teachers) so you know what to buy. Otherwise you'll find yourself spending more money than you need to.
5. Find out when you can get into your classroom to look around and start thinking about how you want to decorate, where to put a classroom library, etc...
6. If you haven't already, hit garage sales and get books for your classroom library. You also may find fun items for your room - like beanbags or pictures.
7. If you're going to have a classroom theme (some do, some don't) start thinking of how you'll tie it all together. I draw mine out on paper so I can get my thoughts together (and because I have a horrible memory!).
8. Plan out your first week in detail. Think about teaching procedures, classroom discipline, etc...
I'm sure other teachers have more ideas, but that gets you started!