What date was Bella Swan's birthday in twilight?

Renesmee was born on the 10th September 2006 by Cezerean which was performed by her father Edward Cullen.

I actually think that it was on the 11th of September because she was born directly before Bella was changed and Bella burned for two days before emerging on September 13th her birthday but I am not 100% posotive so you can take your pick of the two answers.

KatieMcGrath