[corwyn]

This has been answered fairly well so I'll just add a few points that haven't been covered, afaict.

With this character, you'll also need off-hand training for the fast-draw skills you will be using in your off-hand. If you want to build the character so she can use either in the off-hand, this will be 4 points so you might as well get Ambidexterity at that point.

It would also be reasonable, IMO, to buy Dual Weapon (Shortsword right, Knife left). It wouldn't benefit any other weapon combination, including reversing hands, but it would save 5 points. I don't believe it's an official option, but I'd allow it.