You could ask her why she said it. She probably feels responsible for your stutter and she thinks she knows how it affects you and wishes she could take away the negatives of how it affects you. Maybe it is pity. I wish I could not have had my stutter when I was growing up. I am happy with where I am now, but it would be wrong for me to say that I am glad I had a stutter growing up. It was a disability I had. I would view it as your mom expressing her feelings. You are her kid, and she is emotional about something that she is powerless to fix about her kid.