I was between four and five years old.
When our babysitter sent us upstairs for a nap, her "big girl's" bed had a scrap quilt on it. For whatever reason, I don't remember the quilt blocks, but I do remember the quilting - - I would trace the little "roads" with my fingers ... and, how I ever knew that it was a quilt is beyond me, but I KNEW!
My dad's mom was a seamstress supreme, but she didn't make quilts - - just gorgeous gowns and stuff. <wave>