When did you know

So I tested a few days ago and got a positive. My period is 3 days late. So obviously pregnant.

My symptoms almost hit right away about a week and a half before I even tested.

When did your nipples/areolas change (mine were almost instant)

Is it possible to have a period and then not show up on a pregnancy test until later? I know everyone's pregnancy is different I'm just worried I'm further along than I thought. According to my app I'm about 4 weeks.

I just thought it was weird that I had almost all the pregnancy symptoms right away