I won't say much about this because I don't have many regrets, like yeah I wanted to take another high school, the fashion one but no I had to take the path I chose because it was the right one for that moment! And I'm taking some good courses right now that maybe I wouldn't have taken if I chose that school, this is an example but there might be many things I have done like that.
Maybe the only real regret is that I didn't tried doing something when I had a chance and so I lost some opportunities.
But I think that if you learn from your mistakes every thing you did should not be seen as a regret - well I haven't done really big mistakes since I was also little and I couldn't understand some stuff.
Oh looking for a quote I heard about regrets I found this one which is exactly what I wrote, so I end with this quote.