Since Dee Dee lives alone at their old family home and it’s already established that her and Dexter’s parents live up on the house on top of Dexlabs, she’s likely already an adult.It’s possible that Dee Dee might have at least a year over Mandark and/or for Dexter and Mandark to be the same age, since he is in Dexter’s class as far back as elementary school, but we also have to consider the high possibility that he was held back due to his parents’ lifestyles keeping him from going to school during his early childhood. We already know based on evidence from the show that Dee Dee is Dexter’s older sister by just a few years while Dexter and Mandark are only about two years apart themselves (as implied by concept art for “Ego Trip” as explained on the Dexter’s Laboratory wiki). For these characters, I view Dee Dee, Dexter, and Mandark being in their late teens-early 20′s.Now, I will bring up puberty a bit in this–definitely not heavily, but it is mentioned–so keep that in mind. I probably won’t come up with specifics–moreso early/late this or that–for the ages. Still, after some consideration, I’d like to cross reference some of these points to come up with at least a general sense of where these characters may be/have been in their lives. From taking the canon ages of the various CN characters within their own shows into account to people noticing the… liberties, the game took to some of the designs for them in the game, I’m well aware that this is going to be a point of debate.