I'm 5'8" or 5'9" (depending on if I've been to yoga -- ha!) and 190 pounds -- definitely a full-figured gal!
The First looks absolutely cute on me. I think for two reasons -- 1) if I wear the shoulder strap, the strap guard adds width (and if the handles are on my wrist, it's fine, too) and 2) the tassels also add dimension in a flowy way.
So don't shy away from First just because you're tall -- my sister-in-law is 5'11" and the First looks great on her, too.
In fact, I think the City size looks a little clunky on me by comparison. The First is definitely a more elegant bag. But I'll be buying a City anyway and use the color choice to lighten the impact.
IMHO, these bags are so beautiful, they all look great on women!