I have a question i had symptoms before i tested positive and i was stressed out at the time coild that have caused my body not to register the pregnacy at first.

Williams
I had my first sono my dr says its 12weeks and 4days it was done on dec 20th but the fetus seems bigger then 12weeks 4days It seems closer to 16weeks can anyone enlighten me y. The first pic is mine the second one is a 16week so no I found to compare