In this video by Vsauce he discusses mistakes, and it's worth a watch(as are many of his videos). But, there is one part, which I have linked to below, that I found interestingly profound.
In it he discusses an outlook on your past mistakes that I really like. How they stay the same size, no matter how much you grow, but your growth makes them seem smaller.
I like to live my life with very few regrets, I have a couple, but I don't worry about every missed opportunity. If you tend to worry about past mistakes a bit, maybe consider his advice.
And watch the whole video, it's nice.