I remember my first teaching job like it was yesterday, but it was 15 years ago...say what?! I was fresh out of college and full of fresh ideas. I accepted my first teaching position (6th grade science) while on vacation with my family in Hawaii...not a bad start! My lessons were gonna be perfect and I was gonna be the teacher every one wanted. Oh, how I wish I had seen this quote as I went into that year...
I guess I can think of a couple things that I would go back and tell my first-year self. The first would be FLEXIBILITY. This is so important no matter how many years you've been teaching. I had worked so hard in college on how to perfect the best lesson plans. So it needed to go just as I had planned. I've since learned to write lesson plans in pencil, always have extra work for early finishers, schedule in re-teaching if necessary, and allow for surprises...because they will always come!
The second thing I would tell myself is to find an experienced teacher or mentor at your school and keep them close all year long. There's no reason to try and figure out things that have already been figured out. Many districts will automatically assign new teachers to a mentor, but if yours doesn't then find one! They will be an amazing support and resource for you during that first year, and beyond. In a few years you'll be ready to be a mentor to a new teacher. You'll remember how crazy it was and how awesome that person was for you!
Above all else, enjoy your students and enjoy your job. The stresses will come on their own so try your best not to bring them on yourself. Always keep in mind why you chose this profession. It probably wasn't for the pay. Write it down and stick it somewhere on your desk as a daily reminder for when things get rough.
Happy Teaching! :)