Ap Psych exams become harder as the years progress?

on the college board website, they have three free practice exams that were previously administered. one from 1994,1999 and 2012. The 1994 and 1999 exams seemed way easier than 2012, with 2012 I seem to be struggling with half of the questions. I was wondering if any of you guys experienced this and if you could give me some study tips because I’ve recently started to take this seriously and study hard. i take the exam may 7th