As a certified high school history teacher, I definitely agree that the scope of what we teach is absolutely too broad and not in enough detail. Unfortunately, with these big standardized tests looming at the middle and end of the year, we are often forced to rush through or skip things all together.
In an ideal world, we would be able to spend weeks if not months on each era and event in history... but it's just not possible. As the others have said, use your passion to self-educate! Also, if you plan on going to college you should definitely be able to classes that focus on your particular interests!