Is it possible to get a BFP late?

I’ve had two babies and when I took tests I got a BFP pretty early on. I’ll insert pics but I have only been getting really faint lines and I’ve been taking tests since 10 DPO with this possible pregnancy. I’m 18 dpo now (CD: 29) and wondering if it took anyone else a while to get their BFP because I’m kinda freaking out. I’ve had a sids Loss and my son is my literally world so this pregnancy will be such a blessing!

Going to take another test tomorrow .. again xx

These are all separate tests and like I say, they’re super faint 😫