Give it a go, is what I'd say!
I just got a offer from Mansfield College, Oxford, to read english, which I'm really excited about. It seems like a really nice college, and the tutors for english there are really lovely! Its a really small college, but it seems really diverse, so you might find its easy to fit in with people.
My hints for preparation....
Read some introductions to literary criticism/theory. It helps you to look at literature in lots of different ways, and its quite a good topic to discuss in interview.
Look at the research interests of the tutors who will be interviewing you. you can find thesew out on the websites.
Take AEA english!