User blog comment:IamJakuhoRaikoben/Chapter 384: Attack of the Stars, Review./@comment-24264679-20140517214114/@comment-5233713-20140518022756

When Layla retired from magic she gave her keys to a few servants at the condition the key would go to her heirs if and when they decide to do magic. Even if Lucy must have received Aquarius and Cancer around the time she decided to do magic, I think from what is written in the last chapter she could've got Aquarius's key first, which is the reason why Lucy loves her no matter what Aquarius thinks of her. I think the picture of Lucy excited to see a mermaid was explaining how impressed Lucy was the first time she met a celestial spirit.