Proverbs 1:5 (NKJV) A wise man will hear and increase learning, And a man of understanding will attain wise counsel
A wise person has an unquenchable appetite to learn. They never get the place where they imagine that they have arrived, or have exhausted all that they could possibly know on any subject. If you have a heart for understanding, then you are a candidate for wisdom.
The moment a person stops learning they begin to decline. This really has absolutely nothing to do with age. While life experience comes with age, wisdom can be obtained even at a young age. Actually the book of Proverbs is written to young people so that they can gain wisdom. You are never too young or too old to gain understanding, and the wisdom that comes with it.
Proverbs 1:2 (NKJV) To know wisdom and instruction, To perceive the words of understanding.