Answer: Her date of birth is unrevealed. What little is known is that she was found as a child (precise age unknown) by a Jedi who crashlanded on her homeworld of Rattatak somewhere around 40BBY (precise year unknown). Realising her Force potential, he took her as his Padawan and trained her for some years, only to be cut down by a local warlord before he could finish, leaving her to seek vengeance on the warlords who had conspired against him, precipitating her fall to the Dark Side. It's difficult to determine her precise age from all this, but if we assume that she was ten when she was found, and that was in 40BBY, then Asajj would be 28 at the outbreak of the Clone Wars. So figure on anywhere in a range a few years either side of that.