I have been using psychedelics fairly heavily since I was 14 and don't have any real regrets about it  I do regret using some drugs at a young age though. And although I was a fairly responsible drug user at a young age (by comparison), I was also pretty reckless in some ways. If I could go back I would have used less of certain drugs, and used other drugs more responsibly, but in the long run I don't think much if any damage was done. I also think it is harder to use drugs responsibly at a younger age because of prohibition. My main regret is that I didn't have access to some of the drugs I wish I did, and my peer group was largely fairly stupid about drug use and it rubbed off on me to an extent. It is hard to say how much of it is related to the age I started using at, and how much is direct and indirect effects of prohibition...but overall meh I would still use drugs when I started. I think if kids had access to pure drugs, honest information and drug culture wasn't artificially merged with fucktard culture, that it would be much better.