I figured you are tall. Yes, you’re correct. Being tall puts you at increased risk for a pneumothorax.
Remember you have 2 lungs. The left had a bona fide spontaneous pneumo (otherwise, you wouldn’t have undergone the pleurodesis) and the “second” event can potentially be explained away. More on that in a bit.
You still have the right lung that is at risk for a spontaneous pneumo even if you stopped growing.
Hard coughing can cause a spontaneous pneumo too. You may have had a bleb that burst when you coughed too hard.
If your doctor can truthfully write a note saying you’ve only got the one episode of spontaneous pneumo, then you have a chance. He’s got to say the CXR was equivocal (ie didn’t clearly show a pneumo) and CT scan didn’t confirm. Otherwise, 2 cases of spontaneous pneumo is DQ. As part of the waiver, you may be asked to submit results of an inspiratory/expiratory CXR and CT scan. Both should show lungs are fully inflated and no other pathology like blebs or bullae. Finally, pulmonary function tests may be needed too.
For now, you’re DQ for one case of spontaneous pneumo until September 2019. I’m assuming the first bona fide event happened in September 2017 because that’s when you had the surgery.
Someone more familiar with the AFROTC scholarship will need to chime in because I don’t know if they’ll take away your scholarship based on a condition that is temporary or potentially waiverable. The only reason why I think a waiver is possible because the USAF will consider a waiver for all flying classes for history of spontaneous pneumo.
I’m the guy who always has a plan B. If I were you, I would start thinking about one even though you have a chance for a waiver for the reasons I stated above.