Well, welcome to Layo :-)
My personal advice, is that you're going in the wrong direction. I would suggest that you figure what kind of story your character has, then decide on class and race and all that. Figure out the general outline, where they came from, major personality traits, then shade in details.
However, I know that doesn't work for everyone, so if you are set on that, try thinking about what made them a wizard (whether general trends of upbringing, or individual defining events), where they grew up, their family, etc. I know there's a list of questions for character building around here somewhere I'll edit this post if I find it. Poke around, I'm sure you'll find some helpful advice, and you can always read the recently approved character subs if you need some inspiration.
Good luck :-)
