<p>Without knowing anything about you except your ACT score of 31, my advice would be to apply RD to all three, but NOT to apply SCEA to Harvard or Princeton, or ED to UPenn.</p>
<p>The reason is that I think – at best – given your ACT score you will be deferred in the early round as your accomplishments, by your own admission, are not stellar. The early rounds are really for the applicants who have extraordinary credentials, or athletes, or URM’s (if you are a US citizen you would qualify as such, but not as an international student – and your ACT is at Harvard’s low end). So, basically, if you apply to these schools early, you will have wasted your early slot.</p>
<p>What I think you should do is apply to a broader range of non-binding schools early action – schools that do not restrict how many early applications you can send. You should focus on schools where your 31 ACT is in that colleges mid-range of scores.</p>