when can I test!

So I'm still fairly new with this app and all the abbreviations so bear with me! I've been TTC since May, and having zero luck! My fertile window on the app is usually right on the mark with my body, this month my husband and I kicked butt at making sure we BD 2 days before my peak day and my peak day, and the day after. AF is due on December 8th, I'm sick of getting BFN and wondering if I'm taking the tests too soon. When can I test? Do I have to wait until I'm late or can I test earlier? The wait literally kills me! TIA