I think that we are able to change who we are in many ways due to the reasons you have already stated. We will change physically throughout our lives and we are always learning and through education, we change and adapt just as we change with new interest. Where I struggle with this question is if human nature can change as a whole. Sometimes I fear that we are destined to repeat some of the same mistakes we have made through history because of the inability of humans to change.We continue to have wars and horrible atrocities happening all over the world and without some change to the way humans treat one another this cycle will continue.
I struggle with the exact same question that "are we able to change our basic nature". Yeah, I agree that we sometimes repeat the same mistake twice because the first one doesn't change us enough! lol