I actually found that my subjects (French, German, English language, plus AS Lit and philosophy) cut me off from a lot of linguistics options. Some unis (UCL comes to mind) *require* science subjects!
I don't think you'd be at a disadvantage: it *is* a science (there are courses that lean more towards science or arts, but I wanted an arts one and came across mostly sciencey ones), they're all good academic subjects and presumably you have a genuine interest in it. If you did want to bolster your subjects, I'd say take another AS next year in English or a modern language, but you should be fine as you are - lots of background reading and enthusiasm will probably do.
(FTR, I ended up applying for modern languages.)