Even sadder to realize that her isolation began so early. Ten or twelve different elementary schools, something like that, so that she learned it was best not to make friends only to lose them.
And then to note with sudden illumination that something of her lifelong isolation from you yourself perhaps began here. Her lack of insight into the centrality of your own friendships, especially in childhood. All those friends you loved, Pam especially, but also Wes and Lulu and even little Vickie. She took you away from them in search of a chimerical closerness with a best girlfriend from whom she rapidly broke; and she encouraged you not to write to them. Probably that's what her own experience of separation suggested was best.
This isn't to evoke bitterness over your history. Rather to suggest compassion over hers. That her lack of understanding never was from unconcern, rather from lack of childhood friendships of her own to compare yours with. Sad thought.