In my opinion, a mature person is the one who has ability to control and manage his emotions, someone who is not easily angry and always listen to others (parents, teacher, adult, etc.) and then try to separate between what is right and what is wrong so he/she can do the right thing and reject the wrong one. In another way, a child can’t separate and they do what they have heard. A mature person is sacrificed and make others more important, focused on helping those around them and not like a little baby that thinks with a "me,me,me".