They mention many interesting and exciting professions, the most popular ones are a pilot, a cosmonaut, a businessman… As the years pass, they change their minds.
There are always some boys and girls who know very well what they are going to do after leaving school. I think they are lucky. But it is difficult for many boys and girls to give a definite answer about their future profession.
Because of the wide difference in jobs, you should find out all you can about any job which interests you. This may be done by going to the library and by reading widely; also by talking to adults who have different kinds of jobs. You should also think about how well you could do what you would like to do.