In-Game Bio:
Izzy is definitely a chick you don't want to mess with. She knows everything there is about cars, on and off the road. She's got her ride wired tight. She comes from a long line of race fanatics. Everybody she runs with is either a cousin, friend or uncle. They all stick close so don't get on her bad side.

Izzy is the first female Driver in the Blacklist and with that a pretty rare kind. Girl stems from a Family of exclusively racers and has the skill to backup her confidence. She knows her Car inside out and I imagine her to kind of always talk down to other people, because she has a very high opinion of her self. 

Aside from that entirely open for Interpretation.