5A*s will be below average. This doesn't mean you won't be able to get in (people get in with fewer) but it does mean that it's going to be more difficult for you to get in since Oxford, in general, do care about your GCSEs. I don't know what the average is for EM, but I'm guessing it will be between 8-10A*s. Reading is a really good idea. Don't try to cram in as many books as possible since you won't be able to talk about most of them (although it's definitely a good idea to read widely, which you would naturally do if you've got an interest in the subject). Instead, it's very important to read carefully and with insight, making sure you really understand the book and ensuring that you form opinions and are able to respond to it. Talking to others and practicing speaking about your subject is very important. You don't really need to be reading absurdly advanced texts although you can if you want to - at this point, it's just important to get a good idea of the subject and to show the admissions tutors that you know what you're getting yourself into.
Wow, I should mention that I'm not a very high achieving school, and I was under the impression upon researching admissions that higher grades are proportionately more impressive dependent on the average achievement of your school. This is not to say that I'm not going to take your advice, I will obviously and definitely attempt to get as many A*s (hopefully 7) as possible and do well. I've definitely got an interest in reading, and the only fiction book I've really got my eyes on currently is TWOW, which, at the rate, will probably be released by the time I'm applying for uni(; So, yeah, I was originally thinking to cram in as many between now and October 2016, but reconsidering (with internal realization of how much of a bad idea that would actually be, and your comments), I'll try and build as much of a solid foundation as possible by reading books which will help me really gain an understanding on the subject rather than, as you mentioned, being extremely advanced. Do you, by any chance know, if there's any point to taking notes on the books I'm reading? I'll be writing a log just to keep track of the, but I was also considering writing notes on them as well.
Work experience isn't a bad idea, but I don't think that it will add much to your application. Admissions tutors aren't allowed to give you kudos for work experience because wealthier people with better links are more likely to get better placements - giving people who get high profile and relevant work experience is slightly discriminatory. Obviously if something particularly inspiring happens then massively impacts you then you can write about that, but otherwise it shouldn't really take up more than a couple of lines. Work experience is probably more important for other universities.
I understand that work experience won't be the deciding factor/be-all and end-all to my application. However I would still like to do it because I'd just like to make my CV as well rounded as possible, not only for Oxford but future endeavors, and other universities (will expand upon this later).
Don't start worrying about your personal statement now. You'll learn how to write one near the end of Year 12. For the time being, the best things you can do are concentrate on your AS levels (AAAA is what you ought to be getting) and just do whatever you would naturally do to engage your interest in your subject. Finally, don't get in an Oxford frenzy. However much you do, it is still one of the most elite universities in the world and most people do not get in. Do not be fooled by the relatively high entry percentage - the people you're competing against are the best of the best. There are lots of other really great universities in the UK, so don't neglect them. If you convince yourself that Oxford is the only pathway for you in life, you might get a very, very nasty shock.
AAAA is what I'm aiming for in AS, but do you think I should drop one subject for A2? I think it would be less of a workload and it would be easier for me to achieve top grades. I think as for my personal statement, currently I will only make brief points upon what I've done, work experience (don't worry I know it's not extremely important), and my reading into the subject. Then when it to comes to properly writing it I'll just know that I've got a good foundation to base it upon. Also, I should have probably mentioned this, but I completely understand that it's very competitive to get into Oxford. Although I am aiming for it, I recognize that there's a very real chance that I won't get in, and I'm fine with that. Oxford is definitely NOT the only uni I'm considering, but if I end up doing all of this hard work, if it doesn't cut it for Oxford, I'm sure and I hope it'll be good enough for other universities.
Thanks for the response!