Back on topic.
If I read your post correctly you are only a freshmen. As with any ROTC cadet on scholarship, if you decide to leave before the 1st day of your sophomore year, you owe nothing. Essentially, your freshmen year is a freebie to decide whether or not you want to pursue this career further.
As stated, it can land on either side of the fence.
I would suggest to talk to the PMS, but from the perspective of asking the next step(s). My assumption is that they will probably request your medical records and send them for review. HQ AROTC will than do what they are required to do via their medical review boards. It will than come back down the chain to your CoC. It could take months before any decision is given to you.
The reg is pretty straight forward regarding ADHD from my recollection. You must be off meds for 2 straight yrs. and maintain your gpa Your clock just started ticking. Now that does not mean they will disenroll you, but it may be likely they will revoke your scholarship while you remain in the program until you can pass the DoDMERB exam.
Just a parent, but my suggestion would be that you speak to your doctor prior to meeting with the PMS. Ask how long they expect you to be on these meds.
~ Think about it, if you are going into a fight you want to be prepared. In your situation that would be being able to answer the medical questions regarding how long they will have you on the meds.
Hope it helps, again, these are just my assumptions.