Normally, people choose around 10 GCSEs (taken in the school year they turn 16, the school year starts on 1 September). They choose 3-5 subjects for A level.
For GCSE, "minor" subjects can be abandoned -- I stopped studying art, "technology" (design/engineering) and German (since I continued with French). At A level, the majority of students focus on closely related subjects (e.g. maths and science), which I think is the weakness of this system.
Harry Potter has essentially the same system (GCSEs = OWLs, A levels = NEWTs), this isn't something J K Rowling invented.
It's unfortunate your sister couldn't study more subjects. Parents who knew the system might have been able to push the school to allow her to study more, but I can't find anything online where parents/students are grumbling about this. (Again, Harry Potter has the same situation -- Prof. Snape says he only takes the best students into his NEWT class.)
For GCSE, "minor" subjects can be abandoned -- I stopped studying art, "technology" (design/engineering) and German (since I continued with French). At A level, the majority of students focus on closely related subjects (e.g. maths and science), which I think is the weakness of this system.
Harry Potter has essentially the same system (GCSEs = OWLs, A levels = NEWTs), this isn't something J K Rowling invented.
It's unfortunate your sister couldn't study more subjects. Parents who knew the system might have been able to push the school to allow her to study more, but I can't find anything online where parents/students are grumbling about this. (Again, Harry Potter has the same situation -- Prof. Snape says he only takes the best students into his NEWT class.)