birth control!!

so ive been with my boyfriend for about 7 months. i want to take the next step with him but when i do i want him to use condoms, which he doesn't have a problem with, and i was to be on birth control and be on it long enough to work. i have an appointment in 2 days to get it prescribed. so my question is what should i expect? will the doctor look down there? also about how long will it take to begin working?