Procrastinator - A minor is not supposed to be able to (most adult programs that pay via check will put on the check that it is not able to be endorsed by a minor). Either stick with a program that pays via epassporte, wire, or the likes.. or have your parents or someone you know handle the payouts for you in the meantime (just tell them it's mainstream, most adult comapnies use ccbill for checks, or their checks have something like XYZ MEDIA CORP, not JUICY ANAL LESBIAN WHORES WHO SMOKE CRACK LLC.
As far as documentation goes if you are strictly an affiliate you will not need to keep any 2257 documentation on file or anything like that. To be safe you should have a 2257 disclaimer page, that also links to all of your sponsors 2257 pages. 2257 docs are only needed if you are a primary producer AFAIK. Not sure if the rules have changed, but when I was heavily into adult the only people getting raided/inspected for 2257 were actual large production companies. And even then those raids were pretty few and far between, and usually had some merit.