Can we develop our proficiency in MATH or is it purely a talent to become a MATH expert?

It depends. Math is something that you learn, so you could say you develop it. Some people are better at grasping math concepts, though. I remember when I was young, I would understand math almost the instance it was fully explained to me, but it took others a few extra days. I used to think to myself, how are others not getting it? I wouldn't say it is a talent per say, but some people grasp it better than others. Everyone has the same potential in my opinion, though.