I would keep it as brief as possible because doctors are typically very busy. I would introduce yourself so she may remember you from past appointments. Then let her know that you suspect you may have ADHD but your parents are closed to the idea. Then ask if she can help you talk to them.
I imagine she will want you to schedule an appointment to talk in person.
ADDitude Community Moderator, Parenting ADHD Coach, Podcaster & Author, Mom to teen w/ ADHD, LDs, and autism