[Head Trauma years ago = Narcolepsy now?]

I just received 80% SC for my narcolepsy.  The decision took nearly a year but it was worth the wait.

[Head Trauma years ago = Narcolepsy now?]

I was in a HMMWV accident in 1989 and sustained a "closed head injury" and "head trauma".  (They did not use terms like "TBI" in those days...)  I was comatose and intubated for the first day and spent several days in the hospital.  I was recently diagnosed with Narcolepsy with Cataplexy, which can be caused by TBI's.  Would it be possible to try to service connect Narcolepsy with such a long time gap between the initial injury and this new diagnosis?  I have spent decades bouncing between doctors and specialists trying to figure out why I was so tired so I don't have a medical history specifically diagnosing Narcolepsy until 2017.  I do have all my hospital records, line of duty determination documents, etc.