Never Let Me Go 2- Was Kathy Lucky to be at Hailsham?

"That was when I first understood, really understood, just how lucky we'd been- Tommy, Ruth, me, all the rest of us."
(pg. 6)

In the story, the donor Kathy is taking care for frequently asks her about Hailsham and her childhood there. When she tried to ask him about his own upbringing, his face told the story. The author describes the donor as grimacing from his memories, and when he told Kathy where he was from, he did not elaborate nor bring up the subject again. This seems odd to me. Why would some children be sent to grow up in nice places such as Hailsham while others were sent to places like those the donor would not speak of? It seems as though the donor Kathy is taking care of wants to forget his own childhood memories and replace them with Kathy's memories at Hailsham. I’m curious to see the reason behind this. It is beginning to sound a lot like the previous book we read in which positions or statuses in life were already chosen before people were born.