What do you think?

If I have irregular period cycles... Like some months I go 29 days than some 37... But do have a period every month and track ovulation by opk so know when I ovulate.... Is there a chance just bc I'm 13 dpo and get a bfn I could still receive my BFP later? Bc i don't technically no when AF is supposed to be here.. Maybe I'm testing way too early???? Wishful thinking! ❤️ thanks for your help!