Hi, I would say that as important as the grades is your ability to write well about your interest in the subject in the personal statement. You will need to be a bee to quote evidence of your interest over and above what you study in the school curriculum. This would be in the form of books, lectures (online or IRL) podcasts, even debates on historical topics, and perhaps online courses. It’s all the extra work you do because of how much you love your subject. Best of luck.