User blog comment:Nerakil/Bella's birth year?/@comment-3412402-20120424045055

She was born in 1987, according to the first book coming out in 2005. The movie dates are based on the dates the movie was released. They put the wedding as 2011 b/c of the year the movie came out, but it was actually 2006. The "actual" year Bella was born, according to SMeyer and the book, is 1987 and she was married/had Renesmee/was changed to a vampire in 2006, just around her 19th birthday. So, to answer the question, her actual birthday is September 13, 1987.