Wisdom, in my opinion, is earned through experience, but does not require to be a certain age. Not everyone will become wise, but through learning through their experiences and learning things consistantly and often, they'll easily become more wise than they were before. Wisdom comes with experience (provided said experience is REAL). Knowledge is worthless without application and experience.
Some say it could, in theory, be taught, but not specifically. You can teach someone all the knowlegde in the world and they would learn to (eventually) become wise with that knowledge. I have to disagree with their definition, but only that. If our teaching leads to wisdom, it is not the same as teaching wisdom. For example, If I teach someone that Christianity is a lie, and tell them to have a mind that is open to logic and reasoning, and it leads to them becoming an Atheist, I can't say that I have taught them Atheism.
Thoughts?