Congrats on moving to 3rd grade! I think you'll love it! Third graders basically come in as second graders - check in and make sure they know the basics before moving on to the more challenging stuff and (like in kindergarten) practice and teach routines over and over and over! :) Second to third is a HUGE jump though! They are now reading to learn instead of learning to read (most of them).
This book was really helpful for me - https://smile.amazon.com/Every-Teacher-Setting-Running-Classroom/dp/1892989417/ref=sr_1_1?ie=UTF8&qid=1465755946&sr=8-1&keywords=what+every+third+grade+teacher+needs+to+know
and the book Yardsticks will also you give you a good idea developmentally of where they should be - https://smile.amazon.com/Yardsticks-Children-Classroom-Ages-4-14/dp/1892989190/ref=sr_1_1?ie=UTF8&qid=1465755993&sr=8-1&keywords=yardsticks
Don't be afraid to ask for you help from your team or really anyone else in your school who could be of help (other team leads, coaches, etc.)
You got this!!