She may as well forget conventional melee self defence and just pick up a gun. Sure won't be able to shoot the hat off a dude within a week, but it's not hard to kill someone with a gun. Aim and pull. It's deadlyness comes from its simplicity. If she does want to be useful, she should stick with Donny and learn how to conceal herself like he does. Since she lacks the natural strength or the skilk to be kuch use in a fight, she will need to make it up with the element of surprise.