1. Did you go to your first appointment and tell your doc that you think you might have ADD/ADHD, or did you just tell him/her your symptoms and then take it from there?

I thought it, and other people did too, so I was referred and it went from there.

2. What was the screening and diagnosing process like? (Did they ask you a lot of questions, or did they just make you talk? Did you have to fill out questionnaires?)

They asked a lot of questions at the appointment, then they gave a questionnaire to my mother, my school, and myself, then they did a chart and put the scores onto the chart, there was a white and pink and red zone, white being lowest, red being highest.

and lastly, but not least,

3. How long did it take for your doc to make that diagnosis? One session? A couple of weeks? A couple of months?

It took a couple of months for me, however, it can take shorter or longer.
Diagnosing must be done properly, so it needs more exploration into finding out about everything going on and it does take time.