When should I test?

So I'm 17 DPO and AF is now 3 days late. I've had some cramping the past couple days but it's been pretty light and doesn't last very long which isn't how it is when AF is due. I'm also usually dry before AF but I've been having a lot of watery CM. So my question is should I go ahead and test or wait it out a little bit? Any advice would help