There's 2 reasons why she eats her first simply cuze she a zombi second to not let her turn into a zombi after her death
..this girl is hilarious I don't understand her like why did u date him in first place if u like her?? If someone tell me bec she was know the zombi girl loves him so she date him then why she confused when her "friend" told her she interested in him??? And in the flashback its obviously she and this guy date then why the heck did the zombi girl told her "friend she interested in him too?? WTF
If at least u didn't date this guy and give her a confession and she rejected u and date the guy then u have a "reason" as a psych to Kill her...