Ashley Listul (nee Wiswell) is a person of two characters. In real life (and as mirrored in the story), she was a bitch the first time Michael met her. It was a rocky relationship during his Sophomore year/her Freshman year and it was over in a flash. Not the friendliest person.
Later on in life, after having her first kid, she really changed and apologized to him and his sisters for treating them like gutter-shit. Now, they are quite good friends.