I too the iACT in October of 2015 as a sophomore. I didn’t prep because I often don’t for tests, I’m even less likely for any standardized tests. My composite score was 31. Should I start to prepare or am I okay?
I also scored a 31 on my ACT. That is in the 96th percentile of the nation- it is an excellent score. I didn’t study at all either but I regret not studying because I could have obtained a higher score. Take my advice and begin to prep. You will likely be able to pull in a 33 or 34 since you did well without studying! Amazing job! Of course it is not necessary but if you are aiming for schools with high standards (check schools you are interested in for their 25-75th percentile ranges of ACT scores) I would recommend prepping. But, if you are above 75th percentile you will be fine.