My new job has a requirement I don't know if I can fill (Read for details)

So, I scored a new job and it’s a great opportunity, but I have a qualm. First of all, it’s working with the developmentally disabled. I really want it to work, but I have an issue: one of the job “requirements” entails driving a van for the individuals to get to doctor’s appointments, recreational activities and the ilk. The problem is, I tend to crash into things. Often.

So, should I be blunt, and say that’s an issue – but I don’t want to jeopardize the job. I take medicine, which results in bad vision – seeing double sometimes. My vision is not ideal, in addition to the meds. I just don’t want to open up a can of worms, regarding the drugs. (Mood stabilizers for bipolar.) I’d like to keep that private. So, what do y’all recommend? A doctor’s note? A firm stance that I’m not an ideal candidate for driving? Also, I don’t know about when to time this. (I’m only into the job for a week.)
I do have a good rapport with the CCO, and he’s very down to earth, so he might be ideal to talk to.
This is keeping me up at night! Jellies?