Y/n was cursed with immortality after committing blasphemy. They were born in 1900, making them 108(season 4, 2008) when they were 21, ww1 had just ended and everything was looking down. Y/n had cursed god for not helping them and causing a war, so an angel came down and cursed her with immortality. It was permanent. Now after years and years, they’re still 21. At least physically. Now they work at a bar, low profile and gets good pay. When Sam and Dean walk in.