Christopher Paolini is not an original writer and merely rehashes tried and true aspects, themes and quirks from other writers. For example, the dragons in "Eragon" are remarkably similar to the dragons in Anne McCaffery's Pern novels. The theme of a young boy trying to dispose a tyrant has been done to death. He self-published "Eragon" which should show you right there that his manuscript was not considered good enough for mainline publishing.

True, Paolini was a teen when his first books came out.  But there have been other teen writers that come up with far more original stories, settings and characters.  Walter Farley was a teen when "The Black Stallion" was first published and this book is considered a classic which has been much emulated by other authors.