None of us are the same person we used to be. We set New Year's Resolutions with this very goal in mind, putting hope in our potential to do and be better. All of us have grown and changed, having been shaped by the experiences that come with turning another year – or several years – older.
If you're still defining someone by mistakes they made years ago, chances are they're still defining you by yours as well.
If you haven't seen someone for a while and your paths cross, allow yourself the gift of being the first to extend the benefit of the doubt.