At Oxford ppl join the Astrophoria foundation year. It's aimed at ppl with extenuating circumstances in their lives that means they would likely miss the minimum offer of AAA. Although students are enrolled in a College, teaching on the foundation year is separated from the standard undergraduate course. There are also some restrictions such as not being able to stand for JCR posts.
If your teacher thinks you can achieve the entry requirement prob best to consider applying directly to either Oxford or Cambridge. Would recommend going to an open day in the summer to check out the vibe of each university and ask current students what they think about the course, workload, college life etc., to see if this is something you would enjoy. Also check out the course modules and topics to see whether this aligns with your own interests in English. Both Oxf and Camb courses look closely at medieval literature, Shakespeare etc. There's not much 20th century literature, although this is often the topic of the dissertation project.