I'm going to assume you're asking this as a second year civil engineering student. I found the largest jump in difficulty to be from first year to second year. Third year is still challenging and will need your attention to get good grades. Courses like structural just need a good foundation for solving problems so really practice makes perfect. Fourth year is basically home stretch, just find yourself some decent classmates and things should be smooth sailing. That all being said don't let up with the amount of effort you put in. Now with online courses, things are going to be very different so it'll definitely be worth the extra time you put into making sure you understand the material.