CONFUSED!! Help please, How far along was everyone when they found out they were preggers?

Kat
How far along were you when you had your bfp? According to my charts in only 3 weeks 3 days, but I have read a few times at it says around 4 week the egg burrows into the uterus which then caused the body to start making the hcg, which then can be detected in an hpt....so I'm just curious, and a bit confused..lol thanks ladies.