I'm applying for top50 in an American university, majoring in science and engineering. Among the materials required for science application, the university has no requirement for calculus. Therefore, if you want to study abroad as an undergraduate, high school mathematics is enough. Advanced mathematics (including function, limit, calculus, etc. ) is a compulsory course for American college students, so these are all things you need to consider after entering school.
But if you want to learn it more easily, I still suggest that you first make clear the concept and basic problems of calculus in China. After all, reading English math books is a very tiring thing. Moreover, your major is literature and history, and the reading assigned by the professor must be huge, so there is no leisure to grind math books every day.
Come on! For the leisure life in the future, work harder now and finish the advanced mathematics book!