Something similar applies to the UK, at least when I went to university there. Almost everything comes down to exam results on a particular day with (essentially) four years of prep work leading up to that day.

Each university publishes the grades they will accept at a minimum for each major so you essentially choose your major at 17, or really 15 as mentioned above, because you need certain subjects with an “A” result to enroll at the university.

At uni itself, almost all classes are mandatory for a given major with only one or two chances to take an elective. Failing a class at any point usually means either dropping out completely or being moved to a less prestigious major (e.g. “general science” instead of a CS degree).

It’s definitely stressful.