Absolutely normal!
The amount of time you have been pregnant is based on the date of your last period not the point of conception. Most women ovulate 7-10 days after that. So if you ovulate later, say 14 days, and got pregnant 14 days after your period, then at the point of conception, you are “2 weeks pregnant” despite not even carrying a baby at that point. So you can have a bit of a shift in there! Totally normal!
You could've ovulated later than you thought