To learn is not as easy as it might seem, for two very basic reasons. The first reason is that the person doing the teaching actually has to know what they are talking about, and preferably know their subject very thoroughly. The second reason is that those that should be listening, are perhaps actually only half listening, or not listening at all, or are not accepting of what is being taught, or don't actually have the capacity to truly understand what is being taught.
The bottom line is that even when the teacher is a very good teacher that if the student is not ready to actually listen to that teacher and then to do their necessary part to learn and to apply that knowledge, then the learning will not be at the level that it should be at. This basically means, that those that are not ready to receive knowledge, for the most part, are not going to receive that knowledge, which is why those people that opt out in school and various other worthwhile educational environments, do so; because they are no longer engaged, subsequently they have little interest in putting forth the effort to ever get back to actually learning, and consequently they learn very little, indeed.
That is to say, that readiness to learn is a very important component in order to learn. Further to the point, those that may have been good students in the past, may turn into rather poor students in the present, when they so decide that they have learned enough, or know enough, and therefore are not willing to consider additional or new information that is relevant to the world that they live in. On the other hand, someone with a perpetually open mind, that blows where the prevailing wind so has them blow has not developed the appropriate discernment to recognize that not every word spoken nor every word written, is necessarily going to be worth actually assimilating, and thereby need not treat such as reliable knowledge.
While it is never too late to learn, the best time to learn, is almost always when not only the mind is ready, but when the fear of failure or embarrassment, is either non-existent or has been pushed far into the background. The point is that someone that is unduly scared to venture into a new territory is not going to do nearly as well as someone that eagerly wishes to explore that same territory. This is why a good teacher, recognizes that each integral step that is basically in the right direction is something that needs to be acknowledged and praised, for the right words fitly spoken, are a boon and a boost for good knowledge to be successfully received.
Each of us needs to do our part, to correctly prepare ourselves to learn. This means, that part of that process, is doing our homework, getting our rest, researching information, staying engaged as well as current, finding the right study group, and keeping our mind focused on the tasks at hand, so that, in readiness, we learn.