Unfortunately I smoked my first joint at 13, I'm pretty certain it damaged my short term memory. I think had it been legal I wouldn't have got hold of it until much older plus it would have lost some of its cool factor.
It was mostly hash in my day, I actually never liked weed , it was all super skunk loaded with thc that caused paranoia.
Alcohol, cocaine and mdma are rough drugs too but there's something about weed/hash that makes me think it's overall mental effects might be worse. It's odd that it's written off as harmless quite often. (Btw I think all drugs should be legal, but I also now think they are all horrible and have nothing to do with them , well apart from beer and wine!)