Turning 13 soon. What should I expect?

My birthday is in approxmately 12 days. I'm turning 13. I know i won't sprout a face full of acne (some people my age already have) or feel any different at the stroke of 12, but I need answers preferably from people older than 13 who have gone from the transition from tween to teen. Did you notice any changes with attitude/behavior changed during that year? Any major physical changes? What is your story?