I think am interested in becoming and elementary school teacher.
This is school  for children between the ages of 4–11 and coming between pre-kindergarten and secondary education.
Do you know if it is the same worldwide? 
Yes it is, as at 2001 there there were 92,858 elementary schools (68,173 public, 24,685 private) in the USA
I think elementary school is very important for the child development, do you know what are the most important subjects tough there?
Elementary school (United States)
An elementary school is the main point of delivery of primary education in the United States, for children between the ages of 4–11 and coming between pre-kindergarten and secondary education.
In 2001, there were 92,858 elementary schools (68,173 public, 24,685 private) in the United States, a figure which includes all schools that teach students from grade one through grade eight. According to the National Center for Education Statistics, in the fall of 2017 almost 35.6 million students attended public primary schools
first grade", "second grade", and so forth. Elementary schools normally continue through sixth grade, which the students normally complete when they are age 11 or 12. Some elementary schools graduate after the 4th or 5th grade and transition students into a middle school.
In 2001, there were 92,858 elementary schools (68,173 public, 24,685 private) in the United States.
Preschool.
Some private schools, and some public schools, are offering pre-kindergarten (also known as pre-K) as