Do you have a problem understanding words when they are spoken rapidly? Or is it a case of you have a hard time retaining information from lectures and resentations?
I would say if you have a problem understanding words, then this could pose an issue in busy traffic areas, where controllers speak very fast. If it is learning, then ground school could be incredible difficult for you to pass, as they are intense study sessions.
Certainly speak to doctors and specialists, see what they say!