Age is irrelevant.
All factors being equal, adults of different ages learn an instrument at the same speed. A middle-aged student is no slower to grasp reading notes, counting beats, mastering pedals and figuring out the quirky logic of scales and chords. Your innate musical gifts, which doesn't change, for better or worse. Your motivation to learn, which may be greater now than when your parents dragged you to lessons. The amount of time you practice.