What jacket should i wear with this type of shirt?

first off, i'm a girl, i'm just a huge tomboy. i wear a lot of shirts (button-down with intended roll-up sleeves, kind of like a href="http://www.binbin.net/photos/two-stoned/two/two-stoned-grey-button-down-shirt.jpg" rel="nofollow"http://www.binbin.net/photos/two-stoned/…/a in dark colours etc) but it's so damn cold in school that i want to wear a jacket, only i don't bring any because i can't find any jackets that match this style of shirt and also i'm really vain. haha. anyone have any ideas?