jga12 - explain your timeline and situation. You are DQ via MEPS already, or was that part a lie?
The answers to these questions can help you with a review of waiver criteria and qualification criteria to join the military.
Are you a college freshman or Sr in HS?
On medication for ADHD currently or in your past? What dates on medication?
When diagnosed? What other diagnosis besides ADHD? Any criminal conduct?
Do you have, or did you have an IEP in HS?
Your ADHD does not have to define you. Joining the military does not have to define you either. Plenty of options exist to be a successful person without the military.
1) Go to school or get a job and do well without medication and then join ROTC. Or enlist with a waiver after positive documented academic or work performance. This will take 1-2 years off the medication.
2) Enroll in ROTC without a scholarship or contract and complete a year or two not on medication. Try to contract with a waiver after your performance without medication is documented.
3) Take the medication if necessary and finish what you start - every class, every work assignment, and every job. Perform well and be a productive member of society.
Do not stop your medication without the guidance of a physician.