I haven't read all the posts so forgive me if I'm repeating. The Memory quilts I've seen are made with some clothing of the deceased.
One of the earlier posts suggested asking for some of her clothing before it is all gone. I think this is a good idea. But wait to give it to her until she is ready for it. You could make it anytime and just put it away for the right time or put the clothing or items to use away (maybe labeled so you don't forget where they are from and purpose). If you have the items you can make it sometime. And if she never is ready for it and you don't ever give it to her, you know it was still an act of caring for her even if it remains unknown to her.
I agree that a comfort quilt-something to just give her comfort right now would be best for now.