You know we've all done things we aren't proud of. I think that's just part of growing up. I can't seem to understand what you mean by the mistakes you've made but if you're referring things like lying then believe me that's no biggie. We're all human and we all (including you) learn from our mistakes.
I wouldn't try and search for these people to show them that you've improved. It shouldnt take their approval to make you feel better about yourself. I got in touch with some old mates and it really didn't go how it planned. Everybody changes and they grow up to y'know.
I would suggest maybe going to see a psychologist and getting some closure on the issues you have about yourself as a child, teenager and young adult. You'll see that what you're worrying about is not as bad as you make it out to be. You were a child... A teenager ( who doesn't flaw there) and a young adult... (Gosh if I told you the mistakes I made as a young adult, well, we'd be here all day)
honestly go and see a psychologist if you haven't before. It'll probbly only take you a couple of sessions and you'll feel as good as new.
I hope I too made sense and I hope this has helped you in some way.
Harmony