That approach -- making paying more convenient than not -- only works for adults, ie people who have an surfeit of money and a lack of time. High school students are the opposite.
I'm personally fresh out of high school, still 18 in fact. If your price point is so high that your target audience will actually -look- for a pirated version before they even consider a purchase, you are not going to have very good sales. The rule of thumb for DRM is pretty much if anyone can view the content, then the content can be cracked and distributed. Any significantly good, well-known product will be available for free somewhere, it's just a question of how hard it is to find.
Consider that many high school students can't purchase things online anyway, lacking credit cards, which means no matter what, "stealing" the product is more convenient for them.
Consider that many high school students can't purchase things online anyway, lacking credit cards, which means no matter what, "stealing" the product is more convenient for them.