Can An Older Dog Still Learn??

This is a question that I first thought applied to our new dog... which had shown us that she knows NOTHING about doing the business of a dog outside that all other dogs inherently understand... but as I was thinking of the title of this... I realized that it was really just as applicable to me as to the dog... Indeed the dog has already shown that she understands where to "go" when it comes to training pads by the door (although she has yet to "go" outside yet) but even for me... can I learn to be the person God has called me to be... or better yet... not can I learn to be who God has called me to be... can I just simply turn from my rebellious ways and just do what's right?