Paid for a private 3d scan at 14w4d and in one of the pictures my son looks like he has no chin. ultrasound tech said dont worry babies are still developing alot at this stage. can this be a true physical defect or perhaps just the angle? nervous?

Possibilities: There are cases where the angle is just hard to make assessment possible. There are also instances where the lower jaw remains posteriorly positioned leading to some issues in early infancy. Posterior placement of the tongue/jaw can impede full development of the palate in a condition known as the Pierre Robin sequence. Over time the lower jaw does develop & most do quite well.