KH BSS-Zexion Ienzo....

Okay, this is my theory: You saw Ienzo at this age 12 years before the events of kingdom hearts 1. Remember Lea? He was about Ven's age when he met him, but his nobody was like 20. Even in the picture looks like his nobody. Why is that? Because he probably became a heartless soon after BBS. Ienzo, on the other hand, probably turned into a heartless YEARS after BBS. So, long story short, Ienzo had time to grow up before he became a heartless.