What do you think is the defining moment for the main character/person in your book? Why?

The defining moment for Bella was the "moment" when she is turned into a vampire. I think this was her defining moment because she can't take it back. I believe there could possibly be other defining moments like when she gets engaged to Edward but once she was turned into a vampire thats a moment in the story that the main character can't take back. The story can now only move forward. You can be a human and change into a vampire but you can't be a vampire and change back into a human. Now the whole story has done a 360 and Bella has to deal with her life changing circumstances. "There was nothing in the world that I wanted more than him. Would that, could that, change? Was there a human experience that I was willing to give up?" After being turned into a vampire she then realizes that she has moved on and anything that she wanted to do in life, she CAN'T. She has to adjust and now she is questioning whether this was worth it all. A few pages later she has to endure her going away party and has to be careful how intimate her and edward get at the party. They have to be careful how they hug or kiss because anything wrong that they do will give their "non-humaness" away. She was explaining how different vampires kiss from humans. She also has to control her urges to drink human blood which is described in the second book as a vampire's own personal shot of heroine. Bella is now living the life of a true vampire and has to make many sacrifices for the love of her fiance'.