Just to add to that, I knew someone a few years ago who told me a story which I think relates to you. He was a football player in high school back in the 70's I think. Well bodybuilding was becoming a big thing and the coach said he wanted everyone in the gym doing bench presses everyday to build up their chest and give them an advantage over the people they would be facing. The first 3-4 weeks they saw huge gains then nothing, then they noticed they couldn't put up the same amount of weight, then they kept getting injured and were in constant pain. They didn't know back then that muscles need time to heal.

I don't know any good examples to demonstrate to you but basically think of your muscles as millions of fibers, when you exercise you break the fibers it takes 60-72 hours for them to come back together, fully repaired (and technically bigger) if you keep working them they NEVER have a chance to come back together and eventually you will start having serious injuries.
Youth is a very bad thing when it comes to body building, you don't understand your body and your muscles are able to cover up the warning signs that a 30-40 year old man would spot right away.