Do get her the books. They are one of those classic girlhood series that should not be missed. They are beautiful and innocent but also thoughtful: Anne gently questions her ideas about religion, there are scenes dealing with political party lines, times of death and mourning, the hard "what do I want to be" questions and later in the series Anne has children and she and her children have to deal with WWI.
The first Megan Follows movie is excellent. The second one squishes the next 2-3 books in the series together. The third movie is an abomination to the Green Gables series. It is completely removed from the actual events of the series. Can you tell I hate it? I pretend it was never made and am still waiting for a movie to portray the mid-end of the series.
As for my own copies, I got my first set in 4th or 5th grade, read them to pieces by high school and purchased a new set at 18 or so. They are inexpensive. I can't wait for my girls to read them,