User blog comment:JuniperAlien/Artemis...do you trust her?/@comment-4475213-20110926134130

Yeah - the comics showed that she started doing the vigilante thing on her own and it was shortly after she saved KF from the Amazo that GA and Bats popped up to offer her a place on the team. It also implies that she was sick of the life she led with her father and got pissed when he claimed when would always be "one of them".