Should I accept my offer to read Classics at Oxford as an international student?

By some miracle, I've received an offer to study Classics at an undergraduate level at Oxford and have already achieved the required grade. Unfortunately, I am an overseas student and thus would be paying the exorbitant fees. Despite my parents' willingness to pay, this would be a very heavy financial burden that I'm very hesitant to put on them. Oxford and its Classics program have been a dream of mine and so turning this down would probably cause regret, but my sensible side is telling me to forget it. For context, I've been also accepted into the University of Melbourne which is pretigious (if not necessarily for Classics) as well as local for me. Is there any advice for my situation?