Codeine is mild compared to the opiates you mentioned, but it affects everyone differently as its metabolised into morphine via the liver so you can never tell how it will affect you. But as a heroin addict trying to stay clean who started out on codeine I'd advise you to seriously think twice about touching any opiate ever, and to at least wait until your older. Opiate addiction is no life for anyone, especially a young adult like yourself. Enjoy yourself, get pissed with your friends. Live your life a little before you ruin it. I know it seems exciting trying new experiences, but this is one you'll most likely regret. And if you do go ahead with it, just because your not shivering junkie after your first hit doesn't mean your ok. This shit gets in your brain and if you like it and have access to it, you'll carry on until you are an addict. Be careful and look after yourself