Topanga being driven is the key thing. Deep in her heart, she knew she's get into Yale. She also knew that no matter which way she went, she'd succeed. I believe she would have had more regret going to Yale and leaving Cory behind(although, a small part of me believes he would have followed her, doing whatever he needed, if only going to a smaller school close by).

Topanga followed her heart, and in the end, won in both career, and love.