QUESTION ABOUT JOINING THE ARMY????

Im going to list in the ROTC my senior year and i was wondering if your in the ROTC your in the Army correct, after you Graduate? Second question is i was born with hearing loss in my left ear and when i went to the hearing doctor to do the test I failed the Army standard by 5 Decibels which is very close to ping, but what does this mean to me? Does this mean i cant join or that im marginal they will accept me. Please answer im as much detail as you can.