Here is just my own twopence:
Don't be insecure. Make the most positive and confident impression you possibly can. If she brings negative preconceptions into your encounter, it may help her feel that you won't be a pathetic, ridiculed heap of misery but rather a strong, proud, beautiful, happy and wise woman.
Show her that you have made up your mind. Make sure she understands that no part of the burden of making the decision lies on her. Don't let her assume even for one second that you are asking for her permission.
Let her understand that you are not as much running away from a bad situation, but rather towards your own life, finally as yourself.
Don't allow her to think that her insecurity and inconvenience hold up in any way against what you had to go through.
Good luck, Katelyn, I wish you love, understanding and acceptance.
You are ready, show it to her!