Tyberius I partially agree with you.  However, the younger the mind the easier it is to learn.  Which is why it easy for young children to learn multiple languages where as adults have more difficulty learning a second language.  It's almost like a restrictor plate starts to develop the moment we are born and just gets more and more sophisticated as we age.  It doesn't prevent us from learning but it does put a speed limit on the process. 

I believe that at least part of that "restrictor plate" comes from the development of our own habits.  As a child we learn ginormous amounts of information all at once or very quickly and we essentially continue that pace of learning all the way through middle school, high school, and for some people even college.  Always adding more at a steady pace all of our lives.  But once we step away from the learning process, for some it takes only a summer vacation for others it takes years, it becomes harder and harder for us to learn because we're essentially forgetting how to learn.

Yes we all throughout our lives do still tend to learn something new every day but they are small lessons.  Where as, as children from even before we learn to walk we start to learn to speak, what to touch, what not to touch, what shapes are alike, how to move on our own, how different objects feel, smell, or taste.

As children we learn with our entire bodies for several years.  Then over time the amount of new information we gain from day to day decreases and so does our brains "expectation" for new facts.  Until it reaches the point where, when we try to learn a lot of new information once again our minds don't handle it as well and so it takes us longer to learn today than it did 20 years ago.

-Dennis