Да, ошибки есть. Но Вы не расстраивайтесь, пересказ хороший. Советую подтянуть грамматику. А пока:
In Britain it is compulsory for everyone to choose a form of the school education, though most secondary schools continue provide education until the age of 18. Normally between the ages of 5 and 16 years. Exist: comprehensive schools, public schools.
The primary school is indented for 5-7 years old kids/infants ( оба варианта правильны), and Juniors is indented for 7-11 years old. At the age of 11 pupils go to a secondary school, where they stay until their 16th birthday. Also, young people
have the opportunity to pass professional training.( for 14 to 18 years old).
After the young people turn 16, they take/pass (оба варианта правильны) their exams to get General certificate of Secondary Education. Here are assessed their
common knowledge and knowledge in special subjects.
To continue their education at schools or a College students must have their exams' grades in their GCSE not lower than C. Also education can be continued in Sixth Forms or in Sixth Form Colleges. After which they will/are going to take up (в данном случае это практически одинаково. Это просто тонкости грамматики. Выберите любой вариант) GCE A-level. Others will take up GNVQs
(Intermediate or advanced level).
Both GCE a-levels and GNVQs Advanced level are accepted as entry qualifications for higher education in the universities.
P.S. именно Sixth Forms or Sixth Form Colleges. Эта ступень образования сильно отличается от школы. Если хотите, я расскажу Вам в личку. Я хорошо знаю про это.
А то, как было написано у Вас, к сожалению, было с ошибками