I think I have ADHD, and Im not sure how to tell my Parents...?

Do you have a guidance counselor at school? I would suggest speaking to him/her for more direct and personalized advice. I work in Mental Health, and I have seen many parents that have a hard time accepting their child has some type of ADD/ADHD/etc. I think a direct approach would be best; just ask to sit down with her, tell her you are having these problems, and that you want to receive help, be it through medication, therapy, or a combination of both. If she seems resistant to this, don't hesitate to speak further with a guidance counselor, or another adult in your life that you think may be able to help you. You know yourself best, and if you feel that this is a problem that is interfering with your life, then you need to address it before it becomes totally unmanageable. Good luck to you, and I hope you can find a treatment that works for you.