It all depends on where you are, and what laws you're living under. The legal age to view pornography is often 18 or 21. And there are probably even sillier laws for publishing it. Don't listen to people on forums, because most of us don't know what we're talking about. Get some real legal advice before getting into adult sites, or at least check out some of the adult webmaster forums.
If you use a server to host your sites in a country where the legal age is higher than 17 you can be taken to court. I do not know many adult websites that would let you sign upto their affiliate programs because then they would be breaking teh law, they would be fully within their rights to remove you from their program, no matter how muc you earnt through them.
I think age is probably one of the last things you should worry about when starting an adult site.. aren't legal issues the biggest problem? I don't think your age will matter. There's no way of telling how old you are unless you post it on your site. There are already plenty of kids (referring to those younger than you) that sign up for ad networks. Of course you risk getting banned by lying about your age but I think you won't face legal trouble because of your age. Think of how many kids they'd have to put in jail if they actually started tracing those younger than 18 who view porn But, to be on the safe side, it's always a good idea to ask a lawyer of some sort for advice.
I don't think you can start an adult site as in most countries you are not legally allowed to watch porn below the age of 18. So, you can't start such a website as well.
As long as you don't look at the porn I think it would be legal. Though I don't know how you'd accomplish making a porn site without looking at it.
I dont think so its a good idea if you are a minor you can start any other non adult site in present web world non adult sites are earning more than adult sites but they need much more dedication and hard work.
Wait untill you are 21. Then you are safe in all countrys. Starting adult sites is a risky business whatever age you are.