With my first bfp I had a tiny smidge of brown on the Monday (I'm not sure about dpo, but I think it was 10) and had a faint but clear bfp on Thursday evening, which if my guess is correct would have been 13dpo.
With this bfp I didn't have any bleeding or spotting at all but I had pains at 5dpo, which I thought was far far too early for implantation but I did get a real squinter of a positive at 9dpo in the evening and a faint but clear at 10dpo.
I think pretty much anything can be normal!