Symptoms vary wildly from one pregnancy to the next, let alone from woman to woman. A whole range of things can happen, but none of them are a dealbreaker (unless you count your belly growing and feeling those first kicks :P)
Pregnancy is actually calculated from the first day of your last period. This means those initial two weeks aren't technically pregnancy yet since you haven't even ovulated. By the time you realize your period is late, you're technically two weeks along, though your doctor will record it as four weeks.
It’s just easier to track the start of a period than to pin down the exact moment of ovulation. 😬That said, during an ultrasound, your doctor might adjust the timeline if they notice the baby's size suggests ovulation happened a few days earlier or later than expected.