Mate, don't worry about that. Six years ago a friend of mine tried to kiss me at a mutual friend's house party, I backed off and tried not to make a big deal of it. Litterally a few hours later she hooked up with another one of my friends. A few weeks ago they got engaged and I was asked to be the best man at their wedding. I've never seen two people more dedicated to each other - she certainly would never have fallen in love with me, and I wouldn't have fallen for her. I bet she'd be incredibly grateful that she never kissed me, even if she could remember (she drank a hell of a lot that night, and I decided not to furnish her with this information.) No one can ever predict how events might shape the future, life is far too complicated to ascribe one reason for why two people fall for each other, especially a reason as mundane and trivial as "someone else turned her down once". You did not reject her, and apparently you both turned out to be great for each other, a trillion things could have conspired against this eventuality happening - you shouldn't fixate on any of them... It's just the butterfly effect.
"... Tread softly because you tread on my dreams"