Answer:
First of all, it depends on what age level are you asking about. In America, Brownie Girl Scouts are grades 2 and 3, so they are about ages 7 and 8. Girl Scouts and Girl Guides in other countries may be divided differently.
For example: In Ghana, Brownies are ages 7 to 10. In Norway, Brownie Guides are ages 8 to 10. In Spain, Alita Little Wings are ages 7 to 11.
It also depends on the language used by the Girl Guide/Girl Scout organization in that country.
There is a web page on the WAGGGS web site which links to pages for each WAGGGS member organization. Information about the various levels can be found on those pages.