I hope all went well with the first day!!
It is very interesting to know about things in other countries. I am always complicated with k- and things like that and sometimes I even forget what is a sophomore, even when I think I learnt the details here in the forum (thanks to you, DC).
Let's see. In my country we have kindergarten (which is mandatory since 3 years old). At 6, you go to "primaria" which I translate as primary school. Traditionally, primary school has 7 grades. Then you have "secundaria" (secondary school) which could be 5 or 6 years, I will explain later. But in general it was 5. In the 90's we had a reform and primary finished in grade 6, and what was "7th grade" and the 1st and 2nd grade of secondary become grades "7, 8, and 9" in secondary. And 4 and 5 became "1st and second of the EGB, which was an acronym that standed for general basic education. It was a mess, specially because not all the provinces got with it. So, about a decade ago, we were back to the classic: 7 grades of primary, 5 of secondary, unless you were in a special system with 6 years.
What students got 6 secondary grades? Well, many years ago that was for magisterium (people becoming teachers of primary), técnicos (something like Mittelschule, I think), artistic, or those from one of the few schools that were dependent of the university and had a different schedule. All the first allowed to students to have a diploma that allowed them to do certain jobs. Then, magisterium changed (now, it is more professional, and you need to do more study after leaving school). And about those dependent from university...well, before the 80's, there was an exam to allow you to go to public universities. And the students of those schools (which had an extra year, remember) were dispensed from the exam. Then, in the 80's it was established that everyone going to a public university (not to private ones) wouldn't pass a test but they needed to approve a year of a courses that have the purpose of reduce the differences among schools and give everyone a base to go to the university. A couple of classes were mandatory for everyone (one related with citizenship and history of our country, and another related with scientific thinking) and the other were specific of the branch that you wanted to follow. For instance, people wanting to be medicine doctors, dentists, veterinaries, biologists, engineers in agricultural practices, etc, had biology and chemistry. Students of the schools dependent of the university don't do the "general" course, but they have an extra year. So, in time, it is the same. But it is different because it is like an extra year of secondary, at your school, while the other students need to go to other place for its course.
uf, I hope you understood something of all this. I am a product of one of those schools depending from university.
Oh, and years ago we had secondary schools for "commercial" branches and other for the rest. Same years, different curricula. Now it has changed.