-points out that hers would likely still be the group's face-
22 charisma (18 + 4 from aasimar and aasimar variant ability), so +6 and Diplomacy +2 from aasimar and +3 from familiar.
But she's not really a people person. Not a personal people person with most people, anyway.

Edit: Note that this is subject to change if I go with the elven inquisitor I'm working on to pass time because I can't do what I want to do right now. Though I doubt it because I have no interest in this elfquisitor at all.