When to test

Jaci • Baby #1 EDD Oct 16/15!!
So I am a late Ovulater (cd17-22 usually) and my normal LP is around 9 days. All my apps say my AF is due sat Dec 6. I am 7 DPO today. I know you re supposed to wait until 12-14 DPO to start testing, but as my LP is normally not that long, can I start testing earlier? 
Had a temp drop yesterday at 6DPO that was below coverline. Back up high today..