Adjustment of Status - I-485

Hello everyone, on July9th my case status showed me like interview was scheduled and we will send you the interview letter. on July 15th I've received the interview letter with date. My interview is on 14th of August Sacramento, CA. Any suggestions? I already submitted the Medical documents when i filed for the green-card in the beginning, do i need to take again medical test and give the medical reports again? we've Leasing document, Internet bills with both name on that, Joing account, Both names on the Auto and home Insurance, we're paying paying bills from our joint account. are they enough for proving that we're living together? what else i need to take with me? I've filed for GC after a month from my marriage day, that will be any problem? i mean they will ask like why did you applied immediately something like that?My marriage is Genuine and i am living with my wife and her family, i feel so nervous. Your valuable answers and replies highly appreciated .