English is a universal language that we should all learn and try to use it in our daily life. In the context of Mainland China, I truly believe that Mandarin is your mother tongue, but English serves as a secondary language.
And if you are admitted to a programme of Linguistics, you will be required to learn a third language. And of course, you will learn English in depth, such as morphology, phonology, syntax and so on. So try your best to excel scholastically in public examination, and score as high as you can.