Not at all. Email me if you wish: the address should be visible on my details page.
College may well want to formally interview you, though they may not be too bothered given you are in the US and it really is pretty much a formality. I am pretty sure USians and Canadians who were there when I was got away without a college interview. They did me, but I was only an hour from oxford, in London. Cambridge and Oxford don't run according to precisely the same rules in this regard though.
You should certainly know before July. Come July much of Oxford's history and classics bods decamp to sunny places to do research and become unreachable.
I should have a been a proper Byzantinist, really I should, rather than working on early med. northern europe. I can't remember why I didn't now.