I'm now 13 DPO and still no AF. FF says to test on the 25th, so 5 days from now. Should I wait like FF suggests?

I'd say wait...

I woudl also wait for sure until 14 dpo.  the one time I o'ed i got AF on 15 dpo

i vote to wait. just to see what your body does. in the mean time keep yourself stress free, and mentally happy. i firmly believe that helps in getting a positive. :)

looking at your chart, and temp fall...i'd say wait...sorry!

i always let my chart tell me what to do, if my temp is going down then I wait, if its staying high (which it never has....) then I will test