My suggestion would be to speak to her privately and see what is going on. Then make your decision if your "friend" should still be associated with you in your life. I do agree with others that we are stutters and, in general, do not need those types of people in our lives. I want people for me to be encouraging and understanding. It seems OP that her personality has changed from when you two were young. In my opinion, OP is not for the better. We, being people who stutter already, have extreme stresses already wondering if the next sentence that comes out from our mouths will be fluent. Having people around that increases your stress level is not a person to have as a friend. I wish you all the best, OP.