Because in high school, there are many contents of English learning: English grammar, sentence patterns, tenses and so on. And the grammar involved in English is basically completed in high school, so it is very important to learn English in high school.

College English learning is mainly to increase vocabulary. Because you need to recite a lot of words to get the CET-4 and CET-6 certificate. Grammar is in high school, so college English is mainly about memorizing words. As long as you persevere, you can. Good luck with your study! !