Faint line curiosity

Both of my pregnancies ended in misscarriges but I didn't get a positive with first until 4 days after my period was due (didn't realize it was late and wasn't ttc ) but I would of been about 18 dpo with second pregnancy I tested every day I was late and didn't get a positive until 20dpo
​And with both the line was bearly visible on first response pink dye tests
​So my question is has anyways had a late positive that was bearly visible and have had a seccessful pregnancy?