The last three look positive. I bet you get crosshairs for CD20-21 depending on what your temps do. I am pretty sure FF gives you CH when three temps are above the previous six. Does that make sense?
It looks like the last test was starting to go less positive. So I am still guessing CD21ish for your O date.
Just a guess..... but it looks great so far.
I learned a hard lesson a couple months back. Just because FF says you Oed you should not stop BDing. Try to get an extra *session* in 2-3 days after your suspected O date. I really think I O two days after my temps show O. I think we stopped BDing too early all these months and were missing our chance
Good luck! and a boatload of baby