deerslayer15: You may or may not be able to order or purchase the parts you need based on your age. This may, or rather should be something your parents should deal with. I believe it is illegal for underage individuals to order gun parts over the internet. And, I know that if you walked into a gun store and asked for a gas piston for a SKS they would ask you to leave.
I do know that without a gas piston a SKS works only single shot. Was that the intent with that rifle or is it a bad part? Either way, I strongly recommend the 'parental' route and would ask other posters and responders to use a bit of judgement when dealing with a young person. Mikey.