Definitely. Just be honest. If you know that your concerns about your functioning are sincere, which it sounds like you do- so will he or she. Just be relaxed, yourself, and be prepared. I know that's not always easy (I myself am an "ADDer" diagnosed as an adult), but take time to truly examine what your personal challenges are and how they've affected your lifestyle and your day-to-day ability to function. Write it down and read it back a couple times before your appointment. We, or I know I do, tend to get nervous and sometimes seem guilty to others because we stumble over our words or can't quite put them together in a way that communicates our thoughts well to others and I spiral in that type of scenario. Come to think of it though, maybe that's why I was easily diagnosed ;). I remember the disbelief I had at myself upon first considering the possibility that I didn't just suck at life but had an internal glitch in my system, and it was even harder to believe that someone else might be able to see it too. But don't worry, if you're comfortable with whatever dr you see, given that he/she is a competent professional, they won't just write you off as trying to score the good stuff. Treatment/management won't solve your problems but it is certainly the first step in taking control of your life. So good luck and keep on keeping on!
Discuss with him how the ADD is interfering in your life. ex. work, studying, socializing, etc.