She was my college GF, so she didn't have a big dating history at that point. She's married now, to a Mexican dude.

I think being biracial was a big push her to decide who she was. Her mom is white, and growing up in NE PA she had quite a few racist experiences (usually by older white guys) where people treated her and/or her mom like shit because she was black. Meanwhile, the black guys around her probably sweated her as she got older. I'm sure she noticed.