Why is it important to evaluate and selecte literature for children?

Certain pieces of literature are too mature for age groups, which is why almost every library sorts their books by the age they're directed too. While choosing a challenging piece is important, keeping it within their age group is definitely a good step to take. Literature that is too mature may not be understandable at that age, or just have too much adult content, ie; curse words, graphic scenes, etc.

Francis Drake was born in Tavistock, Devon, United Kingdom. 
The year he was born is still unknown till this day, but it is said to be between 1540 and 1544. He was the oldest of 12 boys born to Mary Myllwaye and Edmund Drake.