I mostly agree with you, although I think you overestimate the amount of resources the average college student has available to him or her. I am not sure I completely believe her story either- many of these abortion stories tend to be self-serving, assigning blame for the abortion on everyone else but the woman herself. It is likely what she said happened, but it is also likely that she feared that if she had the baby, people would find out a) she got pregnant out of wedlock and b) she had sex with a black guy.
Also probably feared that her parents would yank her out of college if they found out. And I think we need to keep in mind how difficult information was to come by in the pre-Internet age. I wouldn't believe any college student today who said she could find an adoption agency willing to take a biracial baby off her hands (though she'd still have trouble finding one that could guarantee it would be promptly adopted), but 30-35 years ago, if you couldn't find something you needed in the yellow pages, you were out of options. In this woman's case, it appears that what she needed was an agency who would take her biracial baby immediately after its birth, without her parents ever finding out she'd been pregnant. That's why I don't find anything unbelievable about her story. Sure, she COULD be lying, but if she is, there are still plenty of women who werein her situation in that era who DID have the experience she described. Nobody here has any basis to be branding her a "liar".