Did they tell you to bring anything with you to the intake interview? If not, then they'll probably only talk to you. Eventually you will need to provide documentation of your disability. That would be a short letter from your doctor stating that you are under his/her care since (date) for (disorder). You need accommodations in the form of (notetaker, distraction-free environment for taking a test, whatever you need). They may ask why someone with bipolar needs a note-taker. You could say that the side effects of your medications make it hard to keep up in class. You could have your doctor include that in the letter, too.

They'll ask what is your disability and how does it affect your ability to learn in school. They'll ask what you need to in order to succeed academically. I don't think it's a matter of whether your disability is severe enough, but why do you need accommodation and what kind of accommodation. You basically show you have a disability and how it interferes with school. They want to be sure you have a bona fide disability.

I have a hearing loss and have people transcribing online lectures for me. I also recently developed high anxiety that's taking a while to resolve, so now I have test-taking accommodations in the form of having more time to complete the exam.

Take a deep breath. I'm sure they're willing to work with you.