There is a general perception within society that we become wiser with experience and age. My observation has been that when people (generally speaking) reach about 18 to 20 they start to see themselves as grown-up and having passed the main learning stage (as far as living is concerned - just seeing refinement as required). Yet upon reaching around 30 they see themselves as THEN being much wiser, and so it goes though 40, 60 etc.
There are many things for us to learn in life. In looking at life and growth the real issue seems to come down to far more than what we have experienced. There is the aspect of what have we learnt from what we have experienced? And secondly how astute are we at discerning what is right without such experiences?
For example of the latter, how well do we understand not to murder? Most would argue that they would never murder. Yet many, so saying, have murdered when certain situations have arisen. King David is a classic case in murdering Uriah, the husband of Bath-sheba. Here also, David had committed adultery; which he would have also claimed he would not have done. Would he have been any wiser had he been ten or twenty years older? I don't think so. Having had the experience he learnt not to repeat it. But should we have to commit adultery and murder someone to learn not to do so?
What also stands out as obvious to me is that most bad experiences people have aren't learnt from. These things prove to me that it really comes down to spiritual wisdom: Not age - definately; nor experience - necessarily.
When I hear someone in their 40s (for example) tell me that someone of 14 is too ignorant to understand this or that, my mind immediately turns to Adam. I imagine him rolling on the floor with laughter (having lived 930 years) hearing such a claim. I think, "what arrogance:" Someone supposing themselves to be superior to another person purely by virtue of age.
1st Samuel chapter 3 tells the story of the "child Samuel" who received revelation because the prophet (Eli - who was old at this point) of the time was not listening in regard his sons. Then we have the situation of Mormon.
"And I, being fifteen years of age and being somewhat of a sober mind, therefore I was visited of the Lord, and tasted and knew of the goodness of Jesus. And I did endeavor to preach unto this people.." Mormon 1:15-16
How would you feel about a 15-year-old preaching to you? Would you feel the "he is too young to know," type idea? "I'm more wise than he is?"
What is more, Mormon was appointed to be the leader of the entire Nephite armies at the age of fifteen (Morm 2:1-2). How would you feel knowing the defense of your nation was in the hands of a 15-year-old? Not enough experience? What would he know? He should be at school.
Some may use the old "ah, but that was back then," as if to suggest that people in the past had 3 arms and 3 legs, or were in some mysterious way different to us.
God gave knowledge of the gold plates to a 17-year-old. Wouldn't a 30+-year-old with more experinece have been a wiser choice? God didn't seem to think so. Joseph Smith hadn't got to the 18-20 year old syndrome of settling in to believe he had worked life out. God molded him with an open mind.
This would seem to demonstrate that we must remain as little children in our learning. Heavenly Father is the wise adult. We ALL are the ignorant children that need to learn. If we start to consider ourselves wiser by age then we close our minds that much more. The beginning of learning is to truly realise how little we actually know. And then to realise that we NEED to learn what we don't know, as soon as possible.