This was a very interesting, but confusing day (at least for me)! I'm in the 12th grade (they have a 13th) at Dietrich Bonhoeffer Gymnasium (grades 5 - 13), which is a Lutheran school. School doesn't have an exact time that it begins or ends. It depends on the student's schedule. On some days, classes start at 7:25 AM and I'm finished at 12:45 PM. On others, I begin at 8:10 and finish 2:30 PM. The school is open-campus all day because of the different schedules everyone has. I live only 10 minutes away by bike, so I usually go home for lunch.
Every student of every grade at a Gymnasium (college-bound high school) has a full schedule. What's nice is that you spend more time in two classes that you need to study for your major and minor. For example, I have politics more than math. My classes are politics, English, religion (they offer Catholicism), German, history, math, computer programming (it's in English), psychology, and PE. Everything but English and computer programming is conducted in German. All classes are organized by grade, and at a Gymnasium it's all one ability level (college preparatory). Four of my 5 host-siblings attend the same school; Leonie is only 9 years old and she's in the 4th grade.
This is a "schultuete." It's a cone filled with candy that students receive on the first day of school, to make their day sweeter; 1st - 4th grade!