Hell, you don't even know the character's personality until you've played a few game sessions.
Truer words have never been spoken, if you try to force a personality on them before they are played, it feels forced. Give it a session or 3 (maybe more in a roleplay light game) to develop a personality. Complex PC's are rarely ever appreciated when they show up complex. If you grow complex during the game most of the others will probably grow with you.