[@Scarescrow] The curriculum is different from a 'normal' curriculum by virtue of it being magical in nature. And the way it works in this universe is more like up until around fifth year, the core classes remain the same but you learn more advanced techniques. It's like going from Algebra to Algebra 2 only on a larger scale. It works the same way for the electives, so yes lower year students have more introductory courses while sticking with it advances up the ladder. This continues until reaching fifth year where students start focusing on more specific classes and with it more serious coursework. 

It's not like a 'normal' thing where you take like one year of Gen Eds and then it's all good.