That helps alot, thank you!

See that's what's weird. Very first ultrasound I was given 7 weeks and December 22nd as my due date. When I went to my OBGYN three weeks later she said I'm 10 weeks And my due date is January 4th. But this Friday I'll be 20 weeks which is the halfpoint of pregnancy, which would mean that my due date is off or how far along I am.

Usually an ultrasound in the first trimester is the most accurate. But yes they definitely can get it wrong because due dates are just estimates anyway. All babies grow at different rates and no 2 pregnancies are the same.

An ultrasound is the best estimate.