Anatomy scan tomorrow

Amber
I can't believe it's already time for the big 20 week scan!! (Although they are having me come in at 17 weeks since having twins)
I am seeing a perniatolgist for the first time. Just wondering what I should expect and how might it be different then a singleton scan? 
Trying not to be nervous, but of course sitting here imagining all the things that could be wrong with the twins. 
Also, attaching the pic from 12 weeks anyone else think baby b might be a girl?!