I'm 13.My parents are divorced.My mom has full custody of me.She does not have a Will written out yet.If she dies while I'm still 13 or even 14 can I choose where I live or do I have to go with my father?

So long as the father has legal rights to you then you will be with him.

You have no choice of which parent to live with until you are 18. Until then the courts make this choice for you. Some courts will listen to your preferences but they will still make the decision based on what they fell is your best interests.

Agreed, you have no choice, the courts will decide who you are to live with, if the father has his rights, and wants you, that is normally where you will go.