Languages at Oxford or Cambridge

I am in y12 and thinking about what to do at university next year. I was wondering if the Modern and Medieval Languages at Cambridge or Modern Languages at Oxford would not allow you to apply if you are the nationality of the language you select.

I know they do not discredit A-levels you take if you speak the language and I cannot find any information on the courses that say you cannot be from the country of the language you wish to do.

I am half Spanish, born in England and my first language is English. I do have a some level of fluency in Spanish but I wouldn't say I am bilingual. My mum is fully Spanish but born here (has no Spanish accent when speaking English) and my dad can't speak Spanish at all so we do not speak it at home. All my proficiency has come from a Spanish class outside school and speaking with my grandma. However, I do have a Spanish passport.

I just really find the study of literature and culture that language study involves really interesting and I would want to learn a language from scratch along with Spanish.

Do you think that me being half Spanish would mean I cannot apply for the course or would put me at a disadvantage compared to other applicants?