How do I react?
Generally, if you have to think about how you're going to respond to an attack, it's too late. It's physically impossible to see an attack, process the information, and consciously make a decision on how to deal with it. This is how visual reflexes let us down.
Wing Chun relies on contact reflexes.
Once a bridge has been made with your attacker, applying soft ging (pressure/energy) to their limbs gives you a constant stream of information and enables you to react instantly. Constant chi sau and lat sau practise train these reflexes to the highest level. Your reflexes will be no different to the trained reflexes which protect your eyes or groin.
Everyone can develop contact reflexes.