You don't even know what it means to know something at the med school level yet. Let yourself struggle for a few classes and use the external pressure to shape your studying methods. Until you're thrown into it, your idea of hard/efficient studying effective for med school will just be completely wrong, so you'll spend hours and hours studying only to realize that you barely learned anything useful at all.
Go enjoy your life as much as you can and get healthy habits in place. Once med school starts rolling it becomes incredibly difficult to slow things down and take care of yourself and those around you.