That is totally illogical— they did not know, when she was pregnant, that she would end up being the wife of a two-term president.
And there are pictures of her in high school yearbooks as a Girl. There are zero pictures of her in school as a boy.
Maybe it is because she was never pregnant?
No it’s not.
People from well off families normally take many photos. Michelle was a lawyer in 2001.
Later when someone becomes famous these old photos are then suddenly more important and are circulated.