Hi i finally went to the doctor to get some addresses for therapy and now that i have an appointment I'm scared about how is it going to start?

Like what questions do they ask or do i just start telling them my story?
And is it okay to cry while talking to them?
I have a really complex story and i always start crying when i open up about it. 
And what if I don't get the right "vibe' with the therapist (like not being comfortable with them)

I never had therapy and I'm anxious about the first session ;-;
Can some of you maybe tell me how your therapy started?