User blog comment:Miskos3/Fairy Tail 525: Why Did the Emperor Never Love His Child?, Review/@comment-5303512-20170304145630/@comment-1776824-20170305000140

Unless Mavis was not fully awake for the entire time and it took her time to be able to create the thought projection. For a short time, she was dead, and was kept in stasis because of that crystal. It is entirely possible, and extremely likely, that the thought projection never existed until Fairy Heart was created. Which means Mavis would have learned of everything after the fact by Precht, or by simple process of deduction since she is incredibly intelligent. And again, if Larcade was born of (literal) love and magic, there are many scenarios that exist in which he could be his current age and have been conceived that long ago. The only issue that remains unexplained is when Zeref would have gotten hold of him.