question about CPA's...

so I'm trying to figure out what niche to go with, but I'm having touble.

how exactly do I go for a niche without already knowing what sort of CPA offers I will be advertising?

also, this is probably another very noobish question but as far as getting into a CPA, do I already need my own website or something? i noticed a few of them ask you for your website.

Well, I'm not 100% sure what your asking, but I guess I'll try to answer anyways.

I believe you're asking how to find a niche that has CPA offers, or something similar. The best way to find CPA offers without actually being part of a network is definitely:
There, you can search for specific keywords or just view all offers for a network.

Question 2.
I am afraid to say, almost all CPA networks require you to have a website, and their often hard to get into at all, but visit the stickies in the CPA section, and you will learn how to get accepted.

Hope I Helped,
JIM