[quote=Lennon79]
After rewatching the series, I think Strike Witches are supposed to start as Sergeant before being commissioned as they get older... which probably means I should change mine >>;
[/quote]

Yeah I noticed that, but honestly figured it really didn't matter that much as long as new/experienced recruits weren't high ranking soldiers/officers (unless they are new graduates from officer schools or something). Oh and not to mention that while usually all pilots are officers, tank teams are made up of corporals, privates, and sergeants, so I think you're good unless you really want to change it. 

@VitaVitaAR
In terms of background, newbies and greenhorns are highly favored! But here are some points that may go hand in hand with the personality:

Gallia was previously occupied by the Neuroi, essentially the nation is in ruin and its populate is heavily displaced or dead. Not to mention that since it was very recently liberated, the people of the nation are only just coming back to their homeland. So maybe she lost a parent or friend to the Neuroi invasion when she was too young to fight (They invaded in early 1940 and only just been liberated in late 1944) or something along those lines. In other words, take advantage of the nation of origin's recent history (just think France post Normandy campaign only worse off)