I myself have asked the very same question. As someone who has suffered from mood disorders since childhood and works in the field of social work, I would not tell a boss, professor, co-worker, etc. about my experience with bipolar disorder unless I had established an extremely close, trusting relationship and even then I would be wary of sharing any details. The mental health stigma still exists even among mental health professionals and I would not want anyone to treat me any different than they would any other employee. If thought sharing may benefit me in some way, I would consider it, but even then it's risky. There has been one occasion out of my handful of jobs/internships where I told my field instructor that I had bi-polar disorder. That however was because I was severely impaired at the time and had a break-down in the middle of the day. I felt a relief telling her and know that she was keeping it in confidence, but I know that with other supervisors it would not have been a wise decision. I would strongly urge you to wait and at least establish a relationship with this person before you make any moves. Ultimately, it's your call and what you feel comfortable with.