User blog comment:IamJakuhoRaikoben/Chapter 484: The Monstrous Six, Review./@comment-2214433-20160509190007/@comment-28408126-20160510004105

With that close up picture of Eileen you included, you can actually tell that Eileen is more mature compared to her initial panel shown. But yes, she does look way younger to be Erza's mother, especially in consideration with the 7 year time skip. We don't really have a physical comparison (comparison of physical aging) between a mother-daughter here in fairy tail since most of the mother's are dead (ex. Layla and Lucy, Ur and Ultear). The closest one we have is Lucy and Layla, but then Lucy was still very young at that time and we can't really use that. Bisca and Asuka is not a good example either since Asuka is still very young as well. However, there is still that thought in my head that Eileen is Erza's mother. I've seen in many occasions wherein mothers are drawn very young looking albeit their age, so I don't really want to rule that out yet. She could be like the fairy tail version of Tsunade. haha!