I'm doubting the eight years since the summer sun celebration, most likely AJ just called it the wrong thing by accident, as i don't recall seeing the quilt nor Apple Rose. Also the last proper one wasn't when Aj was a little filly in the photo album there is a photo of her with AB, Granny Smith, Big Mac, Apple Rose, Braeburn and some other ponies giving more confusion, unless 100 moons is equal to 100 weeks which is only about two years, this could provide more explanation as to the time frame? At the end of the episode the moon is show in a crescent phase showing that it does have cycles