Her strength bonus is only one less than her dex bonus at start, so she hits slightly better with dagger, and it does about the same damage as a mace. However, spears are a good option for her since there's a lot of magic ones early on.
actually, I just realise why they give her more dex than strength, they do want her to use a spear as her weapon choice for a big reason coming in the later act 1.
