The biggest difference for me is that in high school everyone I knew was taking the SATs, applying to colleges, and all around obsessing over everything together. As I move forward in my bschool applications, it can feel quite isolating. For many of us, I'm guessing, that's why we come to these forums.
Bschool applications require a lot more organization, project management, and introspection. When people apply to undergrad their goals and interests don't really need to be nailed down. As a rising sophomore, you're getting way ahead of yourself though! Enjoy college, get good grades, and have fun.
Blogging about the MBA application process. Because I need to do something with all this bschool energy.
http://www.mybreakaway.com/ Recent post: September 20, "Transitions"
Yale School of Management MBA Candidate, 2015.