Wow!! She looks in great shape....for her age...lol! :-D
I don't have a model 15, yet, but have heard really good things about them for FMQ. What I really like about your mom's machine is that you can see where the decals are worn on the front right hand side. That is where your moms arm must have rested as she was guiding her fabric through. I hope it makes you feel as if she is with you as you sew on it.